PART 4 War and Diplomacy in Europe

For the next five years, from the spring of 1620 to the spring of 1625, Descartes’s itinerary shows him to be in some of the most critical places for French interests in central Europe. For the first two years, he was bound up with the excitement and horror of war in Bohemia and Hungary, where he almost lost his life in a major military disaster. Then he was in Poland and the German-speaking Baltic, then after a brief return to France in the region of the southern Alps known as the Valtellina, and in Rome, just when France was beginning its Italian campaign. He made many further acquaintances, including members of the Francophilic Barberini family, one of whom sat on the papal throne. His visit to Italy also happened to coincide with the years when Galileo was making a further stir with his book called The Assayer, and there Descartes’s interest in natural philosophy would revive.

But mainly his late twenties were spent moving between battlefield and negotiating table, an active participant in major events even if not one of the notable names. He might be thought to be a volunteer member of the army and diplomatic corps, although fortune would take him in yet other directions. He later underlined those activities in his life at the time in his Discours, although in a veiled way, writing that during this period of his life he was “travelling, visiting courts and armies, mixing with people of diverse temperaments and ranks, gathering various experiences, testing myself in the situation which fortune offered me, and at all times reflecting upon whatever came my way so as derive profit from it.”1 Descartes was certainly becoming wise in the ways of the world.

Into Bohemia

No later than the spring of 1620, Descartes became aware of a delegation of ambassadors from France headed for Ulm. For a generation, France had seen itself as attempting to keep the peace in Europe, well knowing that interlinked personal and political interests meant that a single major conflict could well lead to a general conflagration. But the new king Louis XIII allowed the promptings of his religious conscience to guide his actions, promising to send financial support to the new emperor Ferdinand to put down the rebellion in Bohemia. When that proved to be fiscally impossible for him, he sent ambassadors instead.2

The French delegation crossed into Germany in the spring and reached Ulm on June 6, 1620. According to the seventeenth-century biographer Adrien Baillet, Descartes rushed to greet them, “several of whom were of his acquaintance.”3 Indeed, the leaders of the party included the duc d’Angoulême, one of Descartes’s possible patrons from a couple of years earlier. Another was Charles de L’Aubespine, marquis de Châteauneuf, who had previously served as French ambassador to the United Provinces and the Spanish Netherlands—in later years he would conspire with the duchesse de Chevreuse. The third senior diplomat may also have known Descartes: Philippe de Béthune, comte de Selles, who could have been introduced to Descartes by his father in the weeks between René’s exit from Paris and his departure for The Netherlands. Descartes might also have made a connection to Béthune through Balzac, for Béthune had been among those negotiating with Marie de Medici on behalf of her son Louis XIII, at the Balzac house in Angoulême, in 1619.4 If they had not met previously, Béthune may well have been interested in Descartes now that he had experience abroad; they would later meet again in Rome.

Within a few weeks, Baillet notes, the ambassadors had attracted so many young seigneurs and other persons like Descartes that the French counted more than four hundred horses in their suite.5 They were aiming to arrive at a potential flashpoint before the outbreak of hostilities. At Ulm the army of the Protestant Union, about thirteen thousand strong, faced about thirty thousand troops of the Catholic League massing downriver.6 Angoulême’s party initiated talks between the two sides and on July 3 had obtained their signatures on a nonaggression treaty. Peace at Ulm gave the advantage to Maximilian I, the Duke of Bavaria, however. The army of the Protestant Union under the margrave of Ansbach was now free to move against the Spanish forces that had invaded the Rhenish Palatine under Ambrogio Spinola, but did so ineffectively, while the duke’s own and larger army was now free to restore the emperor’s power in Upper Austria (they would enter Johannes Kepler’s Linz at the beginning of August). Maximilian’s general, Tilly, then headed further east to threaten rebellious Bohemia. At the same time, an imperial army under Charles Bonaventure de Longueval, Count of Bucquoy—another veteran of the wars in the low countries—headed from Vienna into lower Austria to restore Ferdinand’s authority there. First jobs done, the imperial armies of Tilly and Bucquoy joined up and crossed into Bohemian lands. Events would roll toward the Battle of White Mountain, usually taken as the opening act in what became the Thirty Years’ War.

For this part of his biography, Baillet was presumably working from the now lost account of Descartes’s memoirs of his time serving in the wars. He seems not to have known for certain whether Descartes left Ulm with the Catholic army under Tilly or whether he stayed with the French ambassadors and their train, but he thinks it was more likely to have been the latter case.7 Unlike more heavily urbanized lands, in the large spaces of central Europe armed forces could seize ground, cut off approaches, go around, and otherwise maneuver, making prolonged sieges less necessary. A minor French noble attached to the Duke of Bavaria’s party might provide better service by remaining with the diplomats and staying alert to events, or even serving as an intermediary, than taking up space among the horses, kitchens, and baggage of a commander’s entourage. The duc d’Angoulême’s party made their way down the Danube in the hope of negotiating a treaty between Emperor Ferdinand and King Frederick of Bohemia, arriving in Vienna less than three weeks after the treaty of Ulm, on July 20. Having just freed Maximilian’s army for fighting the emperor’s enemies in the east, however, their offers of further diplomatic assistance yielded little response from Ferdinand.

According to Baillet, Descartes then joined the ranks of the young Frenchmen surrounding the comte du Bucquoy. Bucquoy had earned an impressive military reputation in the army of Flanders, commanding the Spanish artillery, and had been ambassador extraordinary to France in 1610; he was much liked by many of that nation.8 Baillet insists, however—perhaps thinking of how Descartes later served the family of Frederick—that the young man did not fight so much as he observed affairs. Perhaps he continued to serve as an intermediary on behalf of the Duke of Bavaria, to whom he would soon return. In any case, there was certainly much to notice. While the Bohemian forces were mutinous because of a lack of pay, Frederick found ways of resisting nevertheless; on the other side, the imperial army started to die in large numbers from the “Hungarian fever”; and regulars and irregulars everywhere resorted to the most horrible acts of violence against the locals.9 As autumn took hold and maneuvering in the field continued, cold and hunger added to the misery.

The final confrontation occurred on November 8, 1620, at Bílé hoře, White Mountain, on the outskirts of Prague. Frederick seems to have been unprepared and his troops were forced into a retreat, which turned into a rout. On the next day, Frederick and his queen, Elizabeth Stuart, fled Prague with their family and retainers. The city was put to the sack, temporarily satiating the imperial soldiers. When news of the event first arrived in Vienna, the French negotiators were so surprised that they awaited confirmation to come from other couriers. They accepted thanks for their unsuccessful efforts in negotiating a peace but stayed on, now focusing on the emperor’s relations with the Prince of Transylvania, Gabriel Bethlen, a vassal of the Ottoman sultan who was trying to revive the Kingdom of Hungary.10 (The French ambassador in Constantinople had made contact with Bethlen in 1619, but the ambassadors in Vienna had little leverage with him, so in 1621 the embassy was recalled.11) According to Baillet, Descartes had been in the field during all these events and contributed to the victory at Prague, still retaining his rank as a volunteer with the Duke of Bavaria. He remained in the despoiled city with the occupying forces for six weeks before campaigning with some of the Bavarian troops into the far south of Bohemia; then he returned to the Duke of Bavaria’s Munich.12

It had been November, with winter coming on. If the imperial army had not headed straight for Prague but more cautiously probed Frederick’s forces, or if Frederick and Prague had been ready to sustain a siege, or if any other of a dozen possibilities had transpired, the imperial army, shrinking already from disease, would have had to go into winter quarters demoralized. Perhaps that would have given Frederick’s potential allies a chance to come to his aid. Perhaps the mooted alliance of Bohemia, France, Venice, Savoy, England, and The Netherlands might actually have emerged as a third force in Europe to calm the divisions between Tridentine Catholicism and militant Protestantism. Only a year earlier, Paolo Sarpi, a friend of Galileo, had allowed his Istoria del Concilio Tridentino (History of the Council of Trent) to be published in London, and editions in Latin, English, French, and German had followed shortly, showing the doctrines of the church not to be infallible pronouncements of truth but negotiated deals struck by international politicking by a princely pope and a centralizing curia. There was talk of unifying Christendom in other ways, without the sword. But also in 1619 the Prince of Orange had the moderate Johan van Oldenbarnevelt’s head removed from his neck, while elsewhere imperial forces took the field to put down any signs of disloyalty to a Catholic emperor. For a moment the world had paused, unsure of which way events would move, with peace a real possibility. But the surprisingly complete victory for the emperor’s soldiers at White Mountain confirmed that other avenues were now closed. Ideology and armies would continue to take precedence over politique negotiation.

Descartes’s early biographers had no doubt that he took a personal part in this change in the fortunes of Europe.13 That means he had served the causes of two bitterly opposed princes, one Calvinist and one Catholic, each using the rationales of dogma to support their power. Yet he seems to have been relatively indifferent to such matters, placing his faith in premonitory dreams and the wisdom of poets. The political morality of the personal and ideological clashes behind the firestorms of Europe were for the greats to decide; he seems simply to have served as intuition directed.

To Hungary and Disaster

Descartes remained with the Duke of Bavaria’s forces until the end of March 1621, when he again left the duke’s army for the Count of Bucquoy’s, then in Hungary. From this point forward, Baillet’s account becomes more detailed, either because he was not required to be the soul of discretion or because the materials he was working from contained more information. Descartes was now definitely involved in the action. Bethlen had refused the terms he was offered by the French negotiators and fought on against the emperor. Bucquoy moved against him first by laying siege to Pressburg/Bratislava in early May, where Descartes saw action. Successful there, the count attacked Tyrnau/Nagyzombat, which did not resist long, and continued east toward Budapest, seizing cities and towns along the way. Descartes acquitted himself well in all these actions, Baillet says; with seizing cities now the main method of attack it was the kind of campaign where officers who knew something about military engineering would be useful.14

But a problem arose at Neuhäsel/Nové Zámky, which brought Descartes face-to-face with disaster. The determined city managed to hold out against Bucquoy’s troops for six weeks. Early in July, in support of those resisting in the city, Bethlen’s forces began to arrive in the field in number, besieging the besiegers, who became trapped between the town’s bastions and the Hungarian cavalry ranging the countryside. With his own troops and horses experiencing hunger, the Count of Bucquoy led a foraging expedition in force on July 10, encountered strong opposition, and in the ensuing fight was killed. Demoralized, and with the rest of Bethlen’s army coming on the scene, on the next night the imperial army lifted the siege and tried to retreat across the Neutra River. The marshy ground on either side made it almost impossible to cross. It must have been a special nightmare for the engineers, trying to save what they could of their artillery and equipment. Less than half the number of men with which Bucquoy had begun the campaign—about eight thousand—made it alive onto Schütt Island in the midst of the river, where they held out for some time. Descartes himself may have thought himself wounded, only to find that after the heat of battle he had felt “a buckle or strap caught under his armor, which was pressing on him and causing his discomfort.”15 Having turned events around, Bethlen went on the offensive. He recaptured Tyrnau on July 30 and from August 18 onward besieged Pressburg, which had been Bucquoy’s first success of the year.16 A truce would be arranged in October. Descartes was now limping through a military collapse, his commander dead, facing defeat and in danger of his life.

Descartes later referred to military action as an example of how he learned to respond to the passions that sometimes overwhelm one in the moment. “For example, when we are unexpectedly attacked by an enemy, the situation allows no time for deliberation; and yet, I think, those who are accustomed to reflecting upon their actions can always do something in this situation. That is, when they feel themselves in the grip of fear they will try to turn their mind from consideration of the danger by thinking about the reasons why there is much more security and honour in resistance than in flight. On the other hand, when they feel that the desire for vengeance and anger is impelling them to run thoughtlessly toward their assailants, they will remember to think that it is unwise to lose one’s own life when it can be saved without dishonour, and that if a match is very unequal it is better to beat an honourable retreat or ask quarter than stupidly to expose oneself to a certain death.”17

Baillet put a good face on things, but Descartes had clearly seen enough. Baillet reports the imperial troops retiring in good order after the death of Bucquoy—meaning only, one supposes, that the defeat was not a rout—with Descartes reaching Pressburg on the night of July 27 in the company of French and Walloon troops (the latter being French-speaking soldiers from the low countries). One can infer, however, that Descartes must have made it to Pressburg with a group of soldiers who had either been fighting rearguard actions in an organized retreat—never a pleasant business—or who had spent some days on the move by night, perhaps from Schütt Island, slipping through territory controlled by enemy cavalry, attempting to make their way to the main imperial stronghold where a last stand was being organized (and which would hold). He would later knowingly write about how it takes greater skill for military leaders “to maintain their position after losing a battle” than “to take towns and provinces after winning one.”18 Baillet would comment that Descartes had become disgusted with the profession of arms (acheva de la dégoûter de la profession des armes). The volunteer had lost the commander he admired and probably tried to impress, leaving him stranded far from France without chance of advancement and even in mortal danger. Baillet probably meant not that Descartes had simply lost his stomach for war, since for some years yet he would stay close to military events, but that he had given up on making his personal mark on the battlefield. It was no romance of knights-errant, or even the straightforward application of practical mathematics, but a dangerous and unpredictable business.19

The Baltic and Return to The Netherlands

Descartes seems to have decided to go far and fast. Whether he did so in the company of others is again unknown but likely. Baillet explained that he wished to travel because he hoped to see a variety of people and customs and to study the grand book of the world (le grand livre du monde, a phrase Baillet lifted from the Discours, although it might originally stem from Montaigne). Baillet says that Descartes did not wish to return to Paris because of internal conflicts there and an epidemic of plague, deciding instead to see parts north. So via either Poland or the Ottoman breadbasket of Moldavia he headed into Silesia, stopping at Breslau/Wrocław (which had just capitulated to the emperor). Baillet denies the rumor that Descartes fought for the Turks because (he thought) the Polish–Turkish war ended at about this time, although in fact Polish resistance proved stronger than expected and the conflict continued into October.20 Military activity in the region certainly continued to make travel difficult—another reason to think that Descartes traveled in company. No one could accuse him of desertion, Baillet continues, since he had joined as a volunteer and, one might add, the commander to whom he had pledged loyalty was dead. But he had now given up serving the emperor in arms.21 Baillet then has the sieur du Perron continuing north to Pomerania on the Baltic coast, which he reached by early autumn.

Could Descartes have been acting on behalf of someone? He could already have been in the region in the spring of 1619. Moreover, on the southern shores of the Baltic, Poland, Sweden, Denmark, and several German princes were contending for dominion, with occasional intervention by the Dutch, whose economy depended heavily on their control of the Baltic trade. The Danes had recently imposed a peace on Sweden that forced the latter to pay war reparations; Christian IV of Denmark was investing the income aggressively, as in building the city and fortress at Glückstadt downriver from Hamburg, which resulted in forcing that great city to recognize his suzerainty.22 Sweden and Poland had entered into a truce in 1618, allowing Poland to start preparing to attack the Turks. In earlier decades, French interests had brought Henri, duc d’Anjou, to the throne of Poland and Lithuania before he returned to France to become King Henri III. Lorraine also had interests there: one of the founders of the ruling house of Lorraine was Christina of Denmark, whose connections throughout the Baltic, North Sea, France, Holy Roman Empire, and Italy no doubt continued to associate the interests of Lorraine with the other rulers. If Descartes were seeking attachment to a person or cause, or were seeking information about current events for anyone in France or Lorraine—or for anyone else—there would have been many opportunities to gather news.

Baillet reports that Descartes began and ended his Baltic visit at Stettin/Szczecin, then under the suzerainty of Pomerania, allied with Sweden but coveted by Brandenburg.23 In Stettin, discussions were under way about the duchy of Prussia, which had been taken over by the Hohenzollern elector of Brandenburg, George William, but which remained a fief of the king of Poland. But he also visited several other port cities. Descartes traveled back and forth in the region for several weeks. Perhaps he was on business for Brandenburg’s adversary, the Count Palatine-Neuburg. Brandenburg was at war with Palatinate-Neuburg in the Rhineland: Brandenburg possessed Cleves, and Neuburg held Jülich. Baillet’s denial that Descartes had fought with the Ottomans might suggest that he was working against Polish-Brandenburg interests. If he were conveying any messages, he would have found a number of sovereign princes nearby. But whatever his reasons, after some time Descartes again decided to go on, this time traveling west to Mecklenburg and Holstein.

In other words, for some reason as the year 1621 wound down, Descartes was moving about along the Germanic edge of the Baltic. From Pomerania westward the territories were part of the Lower Saxon Circle, whose most senior figure was the king of Denmark. When not stopping at the free cities of the former Hanseatic League, Descartes moved through Danish lands. Christian IV yet remained officially neutral in the wars, although sending financial support to Brandenburg and to Frederick of the Palatinate (recent king of Bohemia), who was the husband of his niece, the Winter Queen Elizabeth Stuart. In returning to places he may have already visited in the summer of 1619, was Descartes assessing Danish intentions, or had he even been in their service since his first visit to Copenhagen? Or was he simply passing through because the roads west remained quiet? When King Christian finally entered the war against the emperor in 1625, he would be supported in part by French subsidies.

In November 1621, Descartes started on a final leg home via Holland. The account of Baillet suggests the ending of an enterprise of some sort. Descartes sold his horses and most of his baggage, and he released all his retainers except his valet. One might guess that he did so at the great commercial city of Lübeck, for he then made a short trip overland and at either Hamburg or Glückstadt (on the Elbe) boarded a ship for East Frisia, intending to go on from Emden to West Frisia. From there he could easily travel to Amsterdam and other places familiar from his recent stay.24

But again he was in mortal danger. Having sold most of his things and paid off most of his entourage, he must now have been traveling almost alone and probably not only with his remaining baggage but with money in hand. When he rented a small ship and found some “volunteer” sailors to take it from Emden to West Friesland—presumably paying to accompany them on a trip they were already making—the crew thought he was a foreign merchant. Because Descartes spoke only to his valet, and in French, they did not realize that he understood their language (meaning that arrangements must have been made without Descartes speaking with them). The sailors plotted to murder him as soon as he fell asleep and to toss him overboard, taking all his money and goods. But Descartes overheard and understood. Biding his time, he suddenly jumped up fiercely, brandished his sword, and explained to them in their own tongue, in no uncertain terms, that he would cut them to shreds if they did not proceed as originally intended. They could not stand up to the strong spirit of the chevalier, Baillet says.25 He had been in the wars, and no doubt well understood how to assume the grim face of being in deadly earnest.

Arriving safely in Holland, about four months after the disaster at Neuhäsel, Descartes at last paused for the winter of 1621–22. But even now he seems not to have been acting simply on his own account, for he oddly did not visit his former friend and mentor, Isaac Beeckman. Back in France, in the middle of December, the king’s former favorite, the duc de Luynes, had died, giving free field for the rise of Richelieu, who would be given his cardinal’s hat in April. If Descartes was associated with the government, his managers might have been assessing the direction policy would take.

But Descartes remained active. Baillet reports that he visited the seat of the government of the Dutch Republic in The Hague on three separate occasions, once to see the States General, once to see the court of the Prince of Orange, and once to see the unfortunate Winter Queen, Elizabeth. Was he simply a tourist? He remained keenly interested in the current military situation. The Twelve Years Truce between the Dutch Republic and Spain had recently ended (in April 1621), and the Habsburg general, Spinola, had quickly organized a siege to take Jülich with the support of Wolfgang Wilhelm; the city was held by Dutch troops on behalf of the Hohenzollerns of Brandenburg, who claimed neighboring Cleves but which was also under Dutch control (and where the house of Lorraine also had interests).26 Baillet says that Descartes went to watch the progress of the siege and stayed until it was over. By implication, he continued to be free to move about among the imperial forces, again suggesting an association with Count Wolfgang Wilhelm or Lorraine. Spinola successfully took the city in February, after a five-month struggle. Descartes then went on to the court in Brussels, no doubt to join in the formal celebration of the victory but possibly to keep an eye on what was being planned next in the wars for the Rhineland.

Again in France

Finally Descartes returned to France, first to Rouen and then to his father’s house at Rennes, which, according to Baillet, he reached in the middle of March. And indeed, there is archival evidence of his signing a document in Rennes on April 3, 1622, giving his brother power of attorney to sell the lands he had inherited from his mother.27 This document authorized the completion of the business that his brother had begun in 1618–19, and it may have transferred a sum of money into his hands. Perhaps he had debts to pay. But Descartes would not stay long.

The France to which he returned was in the throes of a new round of internal warfare. Louis XIII was pushing aside the politique policies of Henri IV and Marie de Medici in order to destroy the Huguenots. The ruling family had also, for the moment, made peace with itself, allowing it to present its ambitions less as a personal struggle to retain power than as an attempt to unify the kingdom. Among the other nobles of the day, Louis XIII commanded the greatest ability to raise military forces. But the duc de Montmorency—who had protected Théophile and would soon side with Gaston—warned that the attempt to ruin the Huguenots was an attempt to bring the other rival houses to heel, for it was the Protestants who subsidized the princes and les grands.28

Descartes’s friend Balzac had been in the midst of it. At the time Descartes had left France following the assassination of Concino Concini, Marie de Medici fled to the royal château at Blois, where she was told to remain. But one night in late February 1619, she made her escape and joined an armed escort of the duc d’Épernon and her ten-year-old son, Gaston d’Orléans, and together they headed an aristocratic revolt against her other son, the king. They occupied the seigneurie de Balzac. In the previous year, Balzac had published, anonymously, an open letter on behalf of his patron d’Épernon against the Keeper of the Seals, Guillaume Du Vair, and from then on he wrote often on the duc’s behalf against his enemies. D’Épernon thought so well of Balzac’s talents that he proposed him as personal secretary to the queen mother. One of her former advisers, Armand Jean du Plessis, soon to be known as Cardinal Richelieu, was also interviewed, in his case for the position of confessor, and he insisted on negotiations with Louis. D’Épernon decided to support a reconciliation, and in the home of Balzac’s father, d’Épernon and the queen mother received a delegation of high-ranking negotiators from the king. Balzac put his ability to use by writing three letters to Louis XIII justifying the duc’s actions as necessary for the good of the kingdom. Marie and Louis signed the Treaty of Angoulême on August 10, 1619. But with Richelieu on the scene, Balzac decided not to serve the queen mother but the youngest son of d’Épernon, Louis de La Valette, archbishop of Toulouse, accompanying him to Rome at the end of April.29 (Balzac returned from Rome in April 162230 but then stayed away from court, so on Descartes’s return to France, Balzac would not have been in any position to help a former acquaintance in person.)

In 1622, the royal family having been reunited, Louis XIII began a new round of religious wars, accompanied by a period of severe cultural reaction. Balzac had gone to Rome in the service of the French bishop in whose archdiocese the city government had just horribly executed Giulio Cesare Vanini for atheism and blasphemy. The king himself was pious. Those around Marie de Medici held a variety of views but were generally committed Counter-Reformation Catholics: d’Épernon himself, for example, had recently been warring on Huguenots in Guyenne, and Richelieu had publicly advocated France’s alignment with the Council of Trent. Queen Anne of Austria, too, was devout, and she also secretly kept in close touch with her father in Spain. The policies of the ruling family and its supporters and retainers were consequently increasingly distasteful both to politiques, who put loyalty to the kingdom above religion, and to Huguenot barons, who took steps to organize themselves. From the spring of 1621 onward, therefore, the king had been moving through the country with the queen and queen mother, his favorite the Duke de Luynes, the Prince de Condé, and other nobles, officers, and soldiers, restoring his authority by forcibly seizing disobedient towns, which were often led by Huguenots, before spending the winter of 1621–22 in Paris. (In 1621 the queen mother was restored to the king’s council and began to refurbish Luxembourg Palace with the help of the Flemish painter Peter Paul Rubens; in December, Luynes died of a fever, leaving his recent wife, Marie de Rohan, widowed.)

Then, about the time that Descartes reentered France, the king set off on campaign again. Louis XIII’s army reached Nantes later in the spring of 1622, and headed into Poitou, sweeping up the forces of the Huguenot duc du Soubise along the coast. By early summer the king’s troops were in the south, continuing to take Huguenot cities, sometimes committing horrible atrocities, as at Nègrepelisse. But with the Duke of Rohan keeping up the fight against the king in the south, and with a Protestant German army under Count Mansfeld entering the French north, in Champaign, to create a diversion, a long siege at Montpellier devolved into negotiations and a treaty in October, for the moment reaffirming the cohabitation of the two religious parties in the kingdom.31

Descartes’s movements in this period are little known but intriguing. Baillet explains that having inherited his portion of his mother’s estates, which were in Poitou, he decided to look them over, and then spent the summer in Châtelleraut and Poitiers while his father went to Chavagnes, in the diocese of Nantes, where his second wife had property.32 Father and son had hardly ever lived together, so it is no surprise that they did not stick together now. More curiously, however, they were both moving in the wake of the king’s forces.

Although the younger Descartes now had plenty of military and diplomatic experience, Baillet does not mention him joining in, but one wonders. One of the great lords whose patronage he may have sought, Charles de Guise, led the action against Soubise in the region of La Rochelle that led to a royalist victory in October. Other great lords with whom he had previous contact, the duc d’Angoulême and Béthune, the comte de Selles, had returned from their embassy to the empire and were now with the king. The Balzac family patron, d’Épernon, was there, too. So was one of Marie’s favorites, Bassompierre, being Vanini’s former protector and well connected to the Lorrainers: he had been on an embassy to Spain in 1621 but now fought against the Huguenots so well that in 1622 Louis created him a marshal of France. If the martially experienced Descartes was seeking patronage, he may well have been near the court, on the move.

The sense that Descartes must have been looking for a place is shared by Baillet, who mentions that Descartes’s father had nothing to offer him. Descartes therefore decided to return to Paris early in 1623, Baillet explaining that at last the plague had left it.33 But that reason does not make sense: while plague was certainly an endemic problem in the period, there is no evidence of a major outbreak in Paris prior to 1623. Instead, it began to become troublesome later that same year.34 If Baillet is correct about when he visited Paris, Descartes arrived there at the end of February 1623 (at the beginning of Lent), a full year after his own return to France but just six weeks after the return of the king and his court to the capital city. There Descartes “tasted the peace” that Louis had brought his people by the suppression of the rebels, which suggests he was continuing to associate himself with the monarchy.35 Where had he spent the summer, autumn, and early winter? Given his Italian travels, which come next, a good guess is that the sieur du Perron was in the service of Béthune, d’Angoulême, or another royal official, traveling with the court on campaign.

Paris and the Rosicrucian Scare

When Descartes returned to Paris, Baillet wrote, his friends were happy to learn from him some of the inside news about events that had transpired in the empire. Perhaps Descartes kept up with contacts connected to imperial interests. The war in the empire had continued to go in favor of the duke of Bavaria. A conference had been convened in Brussels not long after Descartes left there, where England hoped to negotiate a peace, but Maximilian of Bavaria continued to act aggressively, seizing Heidelberg and Mannheim. In February 1623—about the time Descartes reentered Paris—Emperor Ferdinand rewarded Maximilian for his efforts by transferring to him the territories of Frederick and his Palatine electoral dignity, giving a secure majority of imperial electoral votes to the Catholics. Even Spain thought this was a step too far in governing the empire, however, and these actions began to turn French policy, too, toward confrontation with Ferdinand. In the aftermath, Lorraine would be caught between France and the Holy Roman Empire.

But the immediate problem for France now lay in the southern Alps. The news from Regensburg about Maximilian coincided with Descartes’s reappearance in Paris, but he was soon on the move once again. According to Baillet, he left Paris after only two months, again moving quickly. He returned to Brittany in May (to consult with his elder brother and possibly his father) and then to Poitou in June and July to see to the sale of his estates—while keeping his seigneurial title—before paying another brief visit to Paris on his way to Italy. Among those he revisited may have been Claude Mydorge and his colleague Claude Hardy.36 He probably also met for the first time Marin Mersenne, who in 1619 had taken up residence in Paris as corector of the Minims based at l’Annociade, their house just to the north of the new Place Royale. (If Descartes was attending the court, he might also have noticed two incognito English gentlemen passing through: the Duke of Buckingham and the Prince of Wales, who were on their way to Madrid.)

But his intention to leave again so soon puzzled his friends. His explanation might have been dissimulating: “That a journey beyond the Alps, would be much to his advantage for the instructing him in business, and gain some experience in the World, and get acquaintance with men verst in Worldly affairs, which he had not yet done, adding, that, tho he might not return Richer, yet at least he would come back from thence more capable for business” (emphasis in the original).37 Or perhaps he really did wish to join in the world of commercial exchange, to which he had been much exposed in The Netherlands and the Baltic. He would certainly have known that during a period of military buildup there was money to be made. Money was beginning to rule the world, he had acquired more than the practical mathematics necessary for keeping the books, he had demonstrated an ability to run risks, and he was disposing of his estates so as to obtain money from their sale, so his explanation is not as ridiculous as it may sound. In any case, he must have decided to prepare the grounds for this new move in late 1622 or early 1623, since the sales could not be accomplished overnight.

Baillet is very clear that Descartes had by now given up most of his former interests in mathematics and natural philosophy. He quotes Descartes writing in 1638 that fifteen years earlier (that is, 1623) he had “quite laid aside Geometry, and would never more meddle with the solution of any Probleme, but only at the request of some friend.”38 Descartes had also decided that mathematics was of little importance when studied for its own sake instead of for use. He forgot most of his arithmetic, although his love for geometry persisted a while longer. But he remained interested in reviving the study of algebra, and in what he called “mathesis,” or universal mathematics. According to Baillet, Descartes also turned to the study of “physic” (physique), or medicine, which in determining the things that made for a good life also led to ethics. Although Descartes had not found the secret for preserving life, he had found out how not to fear death.39 John Schuster’s recent study of the young Descartes’s intellectual development gives no evidence for any interest in philosophy more generally at the time.40

Before leaving Paris, however, Descartes became implicated in the public fear of subversion by the Rosicrucians. In 1623, printed and manuscript handbills and broadsides began to appear in the city, proclaiming that leaders of the brotherhood had come to Paris incognito, possessing wonderful abilities to help their fellow men, and inviting the public to a meeting. A recent study of the episode argues that it was a hoax perpetrated by a medical student, Étienne Chaume, and his friends.41 Some French authors had already heard about the Rosicrucian brotherhood, while versions of the hermetic philosophy that underpinned the Rosicrucian tracts were widespread in the writings of Raymond Lull, cabalism, astrology, and alchemy, to say nothing of the continued interest in the prophecies of Nostradamus and other occult studies. Some French commentators at the time (such as Baillet in later years) also associated the Rosicrucians with a heretical sect known as the “Alumbrados” that had just been identified in Seville, where they were eliminated by the Inquisition.42 Baillet indicates that Descartes, having just come from Germany, was accused of being one of the six leaders of the Rosicrucians who had secretly come to take over France, and that Mersenne in particular—who was just then bringing out major books against all kinds of unorthodox views of God and nature—asked him bluntly about his possible involvement. The answer Descartes gave, according to Baillet, was that the brethren were reputed to be invisible, but that he himself was not, and so he continued to show himself to a “great Concourse of People” and the rumor died.43

But this was no simple jest. Whereas Baillet places the episode early after Descartes’s return to Paris (that is, in March or April), Didier Kahn’s investigations show the handbills to have appeared between mid-June and the end of July, meaning that the public association between Descartes and the Rosicrucians would likely have been made during Descartes’s brief visit to the city in August.44 That was a particularly dangerous moment. On July 11, 1623, the Parlement of Paris had issued orders for the arrest of Balzac’s former friend, Théophile, whom the Jesuit father Garasse accused of being “the head of the band of atheists” (le chef de la bande athéiste) now that Vanini had been eliminated. In August, Théophile was sentenced in absentia to make a public apology (amende honorable) before being burned at the stake; instead, he went into hiding, soon to be arrested at the border as he tried to make his escape to England. Influential friends would make sure that he was only held in prison without trial, and when he finally came to court in 1625 he was acquitted, given that the Jesuit intrigues behind the affair were so obvious. But his example certainly discomfited anyone of libertine sympathies.45

Moreover, among the charges against Théophile was that he had been one of the leaders of the Rosicrucians because a Rosicrucian manuscript had been found among his papers. Théophile might be a scandalous poet, but a long tradition also associated mystical philosophy with eros.46 There had also been other early associations between libertines and Rosicrucian works. For instance, a historian of the movement, John Montgomery, noted that the Rosicrucian General Reformation (Algemeine und General Reformation der gantzen weiten Welt, 1614) was closely based on a work of a satirist and architect from Loreto, Trajano Boccalini, who died in Venice in 1613, perhaps beaten to death for his freewheeling views.47 Théophile explained that the manuscript found among his possessions had been planted, and even went so far as to say that the Rosicrucian placards had been conceived as a means to lure freethinkers into showing themselves for the purposes of identification and suppression.48

He may have had a point. Recent work has pointed to possible connections between the Rosicrucian publications and the Jesuits. A few years later a conspiracy theory originating with them had it that in 1621 an important group of influential intellectuals was plotting to replace Catholicism with Deism. The plot supposedly involved people later identified with Jansenism, such as Duvergier de Hauranne, better known as Saint-Cyran, and possibly even Antoine Arnauld (then a boy). Anti-Jesuit writers including Blaise Pascal and Pierre Bayle would attack this purported conspiracy as a dark and dangerous fantasy meant to create harm.49 There is even a real possibility that some of the earliest reports of the Rosicrucian works come from Adam Haslmayr, a schoolmaster, musician, and alchemist from the Tyrol, a subject of Archduke Maximilian of Austria; Maximilian is sometimes described as “completely devoted to the Jesuits and the Inquisition.” If the Jesuits furthered the publication of the Rosicrucian tracts to root out heterodoxy, they had some success: a friend of Haslmayr’s was implicated in the publishing and imprisoned; the supposed Rosicrucian Haslmayr was himself sent to the galleys of Genoa for four and a half years.50 But whatever the merits of Théophile’s suspicion about supposed Rosicrucianism as a stalking horse to identify and condemn libertines, such people as Garasse were not only clearly drawing associations between Rosicrucianism, epicureanism, and atheism but also working the judicial system to have Vanini executed and Théophile set on a path intended to end at the same place.51 The mood must have been foul.

For Descartes to be called out by Mersenne as a Rosicrucian at that moment was, then, no joke. The witty answer that Baillet says he gave suggests that Descartes remained faithful to the chivalric code and gave no sign of fear. But he was in any case heading for Italy. By the end of August he was gone.

The Valtellina and Rome

Descartes again traveled to a place at the heart of current affairs: to the Alpine valleys known as the Valtellina. The French would postpone military action there for some months, but conflict in the Italian Alps was on the boil. Baillet says that Descartes’s move was prompted by the news in March of the death of Monsieur Sain, who had been a tax collector (controlleur des tailles) for Châtelleraut. Descartes was related on his mother’s side to Sain, who was also the husband of his godmother. Actually, in the Estates-General of 1614, Sain was listed as from Tours, councilor of the king and treasurer general of France.52 Baillet believed that Sain had also taken on the position of commissary general (commissaire general des vivres) for the army in the Piedmont—such positions, looking after the provisioning of an army, could be extremely lucrative.53 The reported “pretext” (prétexte) for Descartes’s journey, then, which he gave to his friends, was that he was both looking into the affairs of his relative and seeing if he himself could obtain the post of intendant of the army. Just in those years such offices were becoming the norm in the French forces, with the intendant looking after the justice and discipline, and finances, of the organization on behalf of the crown. (Intendants also oversaw the provision of military hospitals and care of the wounded, perhaps giving Descartes an additional nudge toward an interest in medicine.) Some of those who held such offices rose to high places in the royal administration.54 Descartes seems to have been seeking to make visible in France some of the skills he had acquired abroad and by doing so to gain favor, since he told his friends that he would learn how to accomplish things in the real world.55 In retrospect, his explanation does seem a pretext, since he did not gain the office, but he seems to have returned with plenty of cash in hand.

He headed straight to the center of action, the Valtellina. A few months earlier those valleys were on the minds of everyone concerned with international affairs, since the so-called Spanish Road ran through them. If Habsburg troops and supplies were to cross from Spanish-held Milan northeast into Austria and Germany, or northwest into Lorraine and the low countries, they had to pass through the Valtellina. The chief overlords of the valleys, the Protestant Grisons, had been supporters of Frederick’s election as king of Bohemia, but a large portion of the population was Catholic. Hard-line Catholic incendiaries had been able to stir up the people of the valleys, who appealed to Spain for protection, and troops from Milan moved in, beginning a series of bloody conflicts that also came to involve the Emperor Ferdinand’s brother, Archduke Leopold of Austria. The marquis de Bassompierre had been sent to Spain to insist that the valleys remain open and that the Protestants remain free to practice their religion, points that were inscribed in the Treaty of Madrid of April 1621.

But by building a series of fortifications to protect their position in the valleys, the Spaniards now not only secured the way north but also divided Savoy from Venice.56 France joined Venice and Savoy in an alliance to force Spain and Austria out of the Valtellina (the Treaty of Lyons, of February 1623). The alliance demanded the withdrawal of Habsburg forces, and Spain backed down to the extent of agreeing to turn its forts over to neutrals, the troops of the papacy. Even more important, following the death of the pope in July the non-Spanish Catholic allies managed to negotiate the election of a reforming and Francophile prince of Rome, Maffeo Barberini. Open war in the Alps would be postponed until the end of 1624, but the diplomatic confrontations were ratcheting up.

It was just then, in August 1623, when Descartes headed straight for the Valtellina. Baillet says that he traveled to Basel and then Zurich, and from there he could have moved farther eastward to arrive at his destination not long after. He would easily have been in the Valtellina long before winter. Baillet thinks that in either Chiavenna or Tirano he must have met the marquis de Bagni, the cardinal and papal envoy who was overseeing the handover of fortifications from Spanish to papal troops (not to be confused with Jean François Guidi, the papal nuncio who was sometimes also known as Bagni and later also befriended Descartes).57 Nearby were French forces under the command of François-Annibal d’Estrées, marquis de Coeuvres (brother of Henri IV’s favorite mistress, Gabrielle d’Estrées), who would lead the French attack on the Valtellina at the end of November 1624. With him was Jean-Jacques de Haraucourt, sieur de Haraucourt, from Lorraine, a favorite of Charles de Lorraine, duc de Guise,58 with whom Descartes seems to have established connections a few years earlier. It is a good guess that Descartes considered himself to be a competitive candidate for intendant, using his personal connections to gain a hearing and offering himself in place of a relative who had already been engaged in supplying the forces.

But he seems to have found service not in administration but in diplomacy—or perhaps the intendancy had been a pretext after all. With a new pope on the throne of Saint Peter, negotiations about Roman troops taking over from the Spaniards were ongoing, and so, Baillet says, Descartes went on to the Tyrol and Venice, stopping on the way at Innsbruck to visit the court of the Archduke Leopold, who also had troops in the Valtellina. He seems to have spent the winter in the mountains, but he arrived in Venice around Lent in 1624. He made sure to be there by Rogation Day—or Ascension Day, the fortieth day of Easter—to see the annual Sensa, or Wedding of the Sea, performed by the doge (which came early in May that year).59 After he completed the business that called him to Venice, he also fulfilled his former promise by making a pilgrimage to the Virgin Mary of Loreto. If he was finished with his business in Venice by mid-May, and made the roughly 250-mile (400-kilometer) pilgrimage on foot, as he said he would, he might have been able to return to the world by the end of June at the latest. Did he return to the Valtellina or otherwise continue to stay involved with current events?

But then, Baillet writes, he thought again of his “pretext” of trying to obtain the intendancy of the French army in the Piedmont, traveling to Rome to negotiate about it. Curiously, however, his visit to Venice had coincided with an announcement by the new pope, Urban VIII, that there would be a jubilee year in Rome beginning at Christmas 1624. Coincidentally, perhaps, Descartes arrived in Rome just before the jubilee opened, at Advent, the end of November; it also happened to be the moment when d’Estrées launched his assault in the Valtellina. In Rome, Descartes saw Władysław IV Vasa of Poland, who had been fighting the Ottomans in Moldavia during Descartes’s passage through that region and had been at part of the negotiations between Brandenburg and Prussia; he again saw Archduke Leopold, whom he had recently visited at Innsbruck; and he met the comte de Chiavenne, from where he had started his visit to the Alps. Baillet remarks that because of the jubilee, Descartes encountered people from every part of Europe, and given his passion for investigating human nature, he spent far more of his time looking into the affairs of men than paying attention to either the ancient or modern sights of Rome. He stayed until spring 1625, when he accompanied the pope’s nephew, Cardinal Francesco Barberini, on the first stages of his embassy to Paris.60

Not much of this makes sense if we think of Descartes as an independent actor who was simply traveling for his own interest and edification. Why would he first be traveling in a mountainous region in the autumn and winter while war was impending? It is an odd place to begin a touristic visit to Venice. His pilgrimage to Loreto was added to fulfill a promise he had made to himself. But then why go to Rome to negotiate about a French intendancy in the Alps? Why remain in the Eternal City for several months and not have a look at the antiquities and the impressive new buildings? He was too old to have a tutor in tow, and his behavior was quite unlike a grand tour as made by other young gentlemen.61 Descartes’s later biographer, Charles Adam, therefore considered Baillet to be filling in some unknown years with speculation about the travels based on Montaigne’s literary account of his own visit to Italy (which was to find a cure at the mineral baths for his illnesses—but Descartes was healthy). A recent biographer, Stephen Gaukroger, agrees that Baillet’s report must have been modeled on Montaigne’s. Another, Geneviève Rodis-Lewis, is suspicious of the whole Italian journey, moving the narrative back to his return to France in May 1625 as quickly as possible. The expert editors of the Historical Dictionary of Descartes and Cartesian Philosophy are also doubtful, simply noting that the trip to Italy was required by “other financial matters” and skipping over any speculations about what he did there. If Descartes was simply acting without purpose, it would all be most mysterious.62

But between June and November 1624 Descartes would have had time to return to the French army in the Piedmont to negotiate about a post, or to do countless other things. Then, when he went to Rome, Baillet reminds us, the French ambassador was Philippe de Béthune, whom we know Descartes had encountered before. For his services to the crown Béthune had been made a Chevalier de l’ordre du Saint-Esprit (something like a Knight of the Bath in England).63 He had been named to the post of special envoy (ambassade extraordinaire) to the Holy See in April 1624, about the time that Descartes was in Venice.64 Béthune was on good personal terms with the new pope: he had spent many previous years in Rome as a French ambassador, and he had helped ease the way for the former Cardinal Barberini when he traveled to Paris in 1601 as the papal legate to Henri IV; both men shared a Jesuit education; both patronized Caravaggio and other painters; and both shared interests in literature and natural philosophy. (In the comte’s case, his collections of “naturalistic” art were extremely rich, later attracting the envy of Queen Christina of Sweden.)

Béthune had been sent to Rome to try to sort out the business in the Valtellina. When d’Estrées finally made his move in November 1624, he quickly took the valleys, as the forces of the pope offered little resistance except at Riva and Chiavenna. Spain in turn allied with Tuscany, Parma and Modena, Genoa, and Lucca; a French-Savoyard army subsequently began an assault on the republic of Genoa in February 1625 while Venice promised to move against Milan. As friendly as the new pope might be toward France, he could not accede to these actions, and he insisted on the return of the fortresses. Descartes had been circulating among the diplomatic hot spots and then came to Rome just when the French attacked, when both Béthune and the papacy needed knowledgeable people nearby on a daily basis. With hostilities now under way, however, the original purpose of Béthune’s embassy was coming to an end. In the spring, the pope went around Béthune by sending his nephew to Paris for negotiations. Descartes set out with that group. How could he not have been connected to events, as before?

The Lorraine connection might have still been active, too. At the beginning of 1625, someone working for Richelieu’s confidant, Father Joseph, transmitted a plan to Louis XIII from Archduke Leopold that would have made for a “Holy Alliance”: aside from France, the archduke of Tuscany would control southern Europe, the duke of Bavaria would rule the Holy Roman Empire, and the duke of Lorraine would rule the low countries.65 Strange dreams were continuing to surface.

Nevertheless, being in Rome at that moment would have a profound effect for Descartes’s future intellectual program. With the new pope in place, the city was abuzz with intellectual promise. Intellectual reformers anticipated that they would be allowed to set Catholic thinking back on the surest path toward a universal understanding of God, through the study of his creation. Among those making a stir in print as well as conversation were the “new philosophers,” who often called themselves “virtuosi.” Libertines such as Giulio Cesare Vanini had excited court circles in France about the view from Padua more than a decade earlier. In Padua, freethinking philosophers and physicians continued to develop ways to show that mathematical and physical investigations of the material world, on the basis of epicurean atomism, could explain all phenomena. Cesare Cremonini was teaching such views at the time Descartes visited Venice. Additionally, Santorio Santorio had just stepped down from the Paduan chair of theoretical medicine, having made the case for explanations of living bodies based on number and matter, with the first edition of his Ars de statica medica (1614) presenting one of the most important early works to use quantitative approaches to medicine.66 By several times a day systematically weighing himself, his food and drink, and all his evacuations, he proved the existence of “insensible perspiration.” Whether Descartes was directly connected with Santorio is unknown, but if he did express an interest in medical theory while he was in Italy, it is hard to imagine that Santorio’s work would not have been a part of the conversation. In Rome itself, the Calabrian monk, Tommaso Campanella, objected to the Paduan line as atheistical but at the same time turned anti-Aristotelianism into a paean for the unity of corporeal nature and animal spiritus. He was then helping Urban VIII to combat astrological rumors of the pope’s impending death.67

Most notably, a friend of the new pope, and of Cremonini and Santorio, Galileo Galilei—former mathematician and engineer of Padua, now philosopher to the grand duke of Florence—had recently published The Assayer. A copy of the book had been presented to Urban VIII with his approbation on October 27, 1623, about the time that Descartes arrived in the Valtellina, and everyone was discussing it.68 Taking the form of a witty and entertaining discourse, it offered a program not only for defending heliocentrism but also for explaining all the knowledge we have of the world as coming via the senses, while they in turn were explained as responding to particles of matter. Heat, for instance, was not a quality per se but a sensation resulting from fiery particles. The material stuff of which the world was made could be subjected to analytical investigation and described mathematically according to its movement in the three dimensions.69 Even a year later, the book must have been among the many subjects discussed by the French delegation. For Descartes, with a sound familiarity with the world from which Galileo had emerged, hearing the familiar echoes of Epicureanism reformulated in terms that a military engineer could appreciate must have been exciting. In all likelihood, like the meeting with Beeckman in 1618, it pulled Descartes back into the orbit of natural philosophical debates, for he was clearly reengaged in them by the time he returned to Paris.

Perhaps Descartes even met Galileo. There was more than enough time for a journey to Florence between his visit to Loreto and his entry into Rome (which was perhaps as long as five months); from April through June 1624 Galileo was himself in Rome, but Descartes could have visited Florence later in the summer or autumn. Having returned from his recent successes in Rome, the sixty-year-old Galileo was then living south of the Arno in the hills overlooking Florence and tending his garden.70 But he was not a recluse, and he received many visitors. If Descartes’s interest in mathematics or philosophy had been rekindled—unknown but likely—then he might well have taken the time to visit. Or perhaps he stopped by when he departed Rome with Francesco Barberini, who had recently been tutored by, and would remain personally very supportive of, the virtuoso; also accompanying Barberini was Giovanni di Guevara, who had been appointed to examine The Assayer with a critical eye but instead became a defender of it.71 Moreover, Descartes’s first biographer, Pierre Borel, insisted that the two had met.72 In 1633, however, when Galileo was famously condemned by the Inquisition, Descartes wrote Marin Mersenne a series of letters disavowing any interest in Galileo’s work while at the same time saying that he was burying all that he himself had been writing for the past three years because he did not wish to contradict any official declarations of the church.73 When asked directly by Mersenne, he said he never had seen Galileo (je ne l’ ay jamais vû), nor communicated with him, nor found anything in his books that gave rise to a feeling of envy or admiration other than his views on music. That is a full and complete denial, which Baillet accepted as a declaration of the truth.74 But it is clear that Descartes knew and respected Galileo’s work, if no more.

Human interventions continued to demonstrate other ways in which power over bodies might affect minds, however. Cremonini himself very carefully avoided confrontation with the Inquisition, even refusing to look into his friend Galileo’s telescope. Despite Campanella’s current assistance to the pope, most of his works were written in prison, where after initial severe torture he spent almost twenty-seven years. (He was released to Rome in 1626, escaping to France in 1634.) More immediately, Descartes arrived in Rome only a few weeks before the burning of the remains of the ecumenical Cardinal Marc Antonio de Dominis and his books in the Campo dei Fiori of Rome on December 21, 1624. De Dominis had once been an archbishop who came to resent papal interference and sided with Venice during the papal interdict of 1606–7. In Venice he also wrote a work on how the refractions and reflections of light on droplets of water could create the effects of the rainbow, a theory often credited to Descartes.75 Afterward threatened by the Inquisition, de Dominis left for England, where he wrote about the superiority of the bishops over papal monarchy and saw Sarpi’s History of the Council of Trent through the press. But unhappy in London, he went to Brussels, recanted, returned to Rome, and was readmitted to offices in the church. For confessing that he believed that a reunion of the Christian churches was possible, however, he was imprisoned, and was awaiting trial by the Inquisition when he died in September. After the posthumous verdict against him, his bodily remains were dragged through the streets and publicly burned. Being in the city at the time, Descartes could not have missed the message being sent about the political pretensions of Rome, even with a cultivated Barberini in charge.

At the end of March 1625, Descartes set off to Paris in the company of Cardinal Francesco Barberini’s delegation, which would make demands related to the Valtellina. Baillet says that he felt it was an important courtesy to help in this way, indicating a friendly relationship with the cardinal.76

But on the way, Descartes left Barberini to attend the siege of Gavi. France had supported the attack on Genoa by the Duke of Savoy, contributing French troops under François de Bonne, duc de Lesdiguières and constable of France, reinforced by soldiers from the Valtellina under d’Estrées. The allied army had moved quickly through Genoese territory but then stopped to take the fortress at Gavi, which resisted. It capitulated on April 22, but the delay had given time to the city of Genoa to prepare its own defense, and with naval support from the Dutch and British failing to materialize, the Spaniards broke through the French naval blockade in August to relieve the city.77 Descartes followed the French troops for a while after Gavi, but then he turned toward Turin, where he met Christine, the young princess of Piedmont (and daughter of Marie de Medici): her husband, Victor Amadeus, was with his father the Duke of Savoy outside Genoa. Perhaps Descartes was continuing to seek patronage in service to one of the armies, but it seems more likely that he was acting on behalf of someone.

At last Descartes returned to France via the Swiss passes—where he took notice of avalanches—meaning that he must have gone through Aosta and Chamonix to Geneva and then Lyon.78 From Lyon and Poitou he sent a now-lost letter to his godmother explaining what he had been able to discover about her husband’s business with the army of the Piedmont, and another from Châtelleraut to his father dated June 24, 1625, discussing the possibility of taking on the position of lieutenant general in the city—which, as we have seen, coincided with aristocratic plotting and Richelieu’s cold-blooded reaction; it would not work out.79 After the better part of a decade, Descartes had returned to France. But he would find no peace.

Descartes was now well experienced in the ways of the world. As Baillet insists, his time had been spent far more on the study of humankind than on anything else. His movements from 1621 to 1625 were closely associated with the major events in Europe, first with the imperial armies in Germany, but also with the French embassy sent to forestall the war. For a while he put his engineering abilities to use, but the death of the count of Bucquoy meant the death of a possible military patron. After the defeats in Hungary, he had moved through the southern Baltic, perhaps on business related to the junior Palatine house. When back in the low countries, he certainly kept a watch on events in Jülich from the imperial side. Then in France he is likely to have been with the king’s army on campaign, too. He stopped only briefly in Paris, coincidently with the Rosicrucian scare, since the sale of his estates went forward and he made a rapid departure into the Italian Alps, in the midst of war, perhaps seeking a military administrative office but certainly moving among the diplomatic hot spots. Then, after fulfilling his vow to visit Loreto, he was in Rome for the opening of the papal jubilee, just when the French attack on the Valtellina began, again visiting with dignitaries and keeping a watch on the human comedy rather than attending to the sights. He must have encountered the latest discussions about the new philosophy while there, as well. His return to France began in the company of the papal envoy but was delayed by yet further military interests. The certainties of his world had come apart, he had survived real threats of death on more than one occasion, and he was truly speaking to power. He kept moving.

How one wishes to know for whom he was working or from whom he was seeking office, or to know the several persons! Bourbon, Guise, Lorraine, Sully, Wittelsbach, perhaps Denmark, Barberini, even Savoy, each in their turn or all together might apply, but certainly not either Jesuits or Huguenots. The simplest explanation holding them together is that Descartes remained loyal to the interests of the queen mother. In any case, none of the possible connections would have identified him as disloyal to France, although from the mid-1620s onward, that would change. In a different world some decades later, Baillet clearly thought it best to avoid the subject. The efforts of Louis XIII to eliminate all internal opposition and to physically control Savoy and Lorraine would continue to stir many nobles to dissent, sometimes to take up arms against him. Many of the persons in the kingdom whom Descartes is likely to have served would, in the end, not sit happily at the young king’s table. By Baillet’s day, Lorraine, for example, had been reclaimed by France, driving the ruling house into service to Louis XIV’s enemies, the Viennese Habsburgs.

The sieur du Perron may, however, have stumbled across another approach to bridging division and uniting the world: he had bumped up against the illuminating excitement of Galileo’s physicalist explanations of nature and our body’s sensations of the world. Resolving human conflict not by burning heretics and atheists, or executing dissenters, but by burning away all the fantasies that could not be established on the basis of clear and distinct ideas, the kind of evidence that existed in three dimensions rather than in unverifiable qualitative attributes: creating harmony and bodily betterment by establishing the real facts: a noble, universal, millenarian dream. We know at least that he placed much weight on dreams and the truths spoken by poets. Perhaps powers other than the sword now pointed a way forward.