Around 400 CE, the Chinese poet Tao Yuanming penned his vision of the ideal world:

The gentle south wind comes with the season,

its whirling gusts blow open my robe.

Breaking with social contacts, I enjoy leisure activities;

lying around, or sitting up, I play with zither and books.

Of garden vegetables, there is a surplus,

last year’s grain is still in storage.1

At the other end of Eurasia, Palladius Rutilius Taurus Aemilianus, a landowner in the Roman province of Gaul in the fourth or fifth centuries, embarked on a guidebook for novice farmers. His advice would help them tend a paradise as halcyon as that portrayed by Tao, one with inexhaustible wells, verdant fields, a clement atmosphere, orchards laden with fruit, and well-built roads.² After more than a thousand years, the dream of men living in harmony with nature had hardly changed.

But the Arcadian idylls of Tao and Palladius were written amid societies mired in political decay. Across Eurasia, the period between 250 and 500 was one of imperial regression. The Western Roman Empire was overrun by barbarians. Remnants of the old imperial grandeur lived on in Constantinople, but the Eastern Roman Empire would never attain the same power as that of the first two centuries of imperial Rome. In China, barbarians swarmed over the kingdoms into which the Han Empire had splintered. In South Asia, the zenith of the Gupta Empire was comparatively short-lived. For a while, the newly established Sasanian Empire stood out as an exception, but by the end of the fifth century it too had degenerated. The rest of Eurasia comprised a cockpit of fighting and fluctuating alliances as relatively small polities – such as Funan, the Pandyan kingdom, Goguryeo, and the Yamato kingdom – along with nomadic societies and migrating peoples struggled for survival and supremacy.

The Völkerwanderung

The period from the third to the fifth century saw the two great centres of power, Rome and China, succumb to a combination of internal weakness and unrelenting migratory pressures. The fatal thrust came from the heart of Eurasia, where the plains and valleys of Mongolia and Central Asia were inhabited by the Xiongnu and the related people known collectively as the Huns, who comprised various tribal groupings – White Huns, Red Huns, Hephthalite Huns, to name but a few. The core of these genetically and culturally related societies consisted of confederated bands of nomads who followed their cattle from pasture to pasture on horseback. On the fringes of the Mongolian and Central Asian grasslands, semi-nomads and traders maintained relations with sedentary, agricultural societies, which looked down on the wandering peoples. They perceived them as wild, bow-legged beasts, hardened by the harsh climate. ‘They can withstand wind and rain, fatigue, hunger, and thirst,’ nervous Chinese officials reported.3 Perhaps unsurprisingly, the Huns saw themselves rather differently. An inscription from northern India, for example, is fulsome in its praise of one Hun leader: ‘His heroism … was specially characterised by truthfulness, the earth was governed with justice.’⁴

In the third century, relations between wandering tribes and agricultural centres were profoundly disturbed. This was partially caused by environmental changes. The climate became so severe in Mongolia and Central Asia that the Xiongnu and the Huns were forced to move. Dendrology shows that the steppes became drier between 242 and 293.⁵ It was around this period that clashes between the Xiongnu, the Xianbei, and the Chinese along the Yellow River became more frequent. In 311, Xiongnu warriors sacked the Chinese capital, Luoyang. At about the same time, the Huns left their homeland on the banks of the Volga. Although we generally think of the Huns as exceptionally savage warriors, their 4,000-kilometre journey was appallingly tough and troubled by deprivation. In 370, they crossed the Don and reached the Danube a few years later, where they clashed with the Goths, who dwelt in that area. The exodus of the Goths panicked their fellow Germanic peoples who lived along the borders of the Roman Empire. They fled, overrunning the Roman limes. Bishop Ambrose of Milan explained the cataclysm. ‘The Huns threw themselves upon the Alans, the Alans upon the Goths, and the Goths upon the Taifali and Sarmatians.’⁶

The same climatic change that drove the Huns out of their plains, combined with overpopulation, accelerated the migration of the Germanic tribes from the Baltic region south towards the plains between the Rivers Elbe and Rhine, and onwards to the Black Sea. For centuries, the Baltic had been a transit zone for both trade and migration. But this exodus was far larger and more destabilizing. Consider the Goths. They originated in the Danish Peninsula; settled along the Elbe around the first century, where they clashed with the incumbent tribes; then moved on to the Danube around 350, where they clashed again, this time with the Roman legions. Gradually they became involved in Roman infighting over the imperial succession, resulting in the deaths of thousands. Conflicts between the Gothic tribes, over land and leadership, were also rife. And then they were plagued by famine and by the vanguard of the Hun incursion. In what was more an act of desperation than of aggression, the Goths finally crossed the Danube into the Roman Empire. Now they were at the mercy of local leaders, who allegedly enslaved Gothic children in exchange for food. In 405, the Goths could endure no more and marched on Rome to demand land and rights.

Another major Germanic people, the Vandals, did not fare any better. They had traversed the Baltic Sea in the second century, instantly coming into conflict with the tribes already there. Around 270, they moved on to the Danube, where they made a pact with Rome to stay on the northern bank. When the Goths arrived, they begged the Romans in vain for permission to relocate. But defeats by both the Goths and the Huns forced them west, following the Danube into present-day Slovakia, Austria, and Switzerland. Still dogged by the Huns, they reached the Rhine in 406, where they ran into the Franks and lost tens of thousands of lives in the ensuing battles. In 409, the Vandals crossed the Pyrenees into Spain, where their settlements were soon threatened by the migrating Visigoths. In 429, they finally traversed the Strait of Gibraltar to Africa, where they fought off Roman troops and Berbers to found the Vandal kingdom.

For the Vandals, Goths, Burgundians, Saxons, and the many other migrating peoples, their odysseys towards the temperate farmlands of Western and Southern Europe were long, arduous, and violent. These were not short, sharp, military invasions but a Völkerwanderung: sustained migration crises caused by a combination of climatic change, hardship, insecurity, and the lure of wealth. They rapidly spiralled out of control, first into wars with the peoples already inhabiting the lands they entered, and then, fatally, with the Roman Empire itself. The armies of the migrating peoples contained tens of thousands: the Hun army that reached the Roman heartland, for example, fielded around 60,000 warriors. But even hordes as large as this would probably not have prevailed if the imperial structures had not already corroded from inside.

The Fall of Rome

In April 248, hundreds of thousands of Roman citizens flocked to the Colosseum and the Circus Maximus. Banquets were laid on, extra bread handed out to the poor. Special coins were stamped with slogans like Romae Aeternae and Saeculum Novum to commemorate a new age for the eternal city. According to the Roman calendar, the city had been founded exactly 1,000 years earlier, a millennium adorned by a long chain of triumphal arches. The Romans undoubtedly enjoyed their celebrations, even though many must have wondered whether the empire’s future would continue to be triumphant. Rome had just recovered from a turbulent period during which five emperors ruled in less than a year. The city had been engulfed in religious strife between pagans and the growing community of Christians who no longer wished to stay hidden away in its underground catacombs. In 250, the new emperor, Decius, ordered that all citizens must pray to the gods of Rome. Ominously, the decree was followed by an outbreak of plague that, at its peak, killed 5,000 victims a day in the capital city.

The Christian writer and recently appointed Bishop of Carthage, Cyprian, wrote of a world order that was passing away.7 Only heaven could bring salvation from plague and oppression. Meanwhile, messages reached the capital with news of emergencies on the empire’s borders. The emperor at the time of Rome’s millenary, Philip the Arab, had been forced to sign an embarrassing peace treaty with the Sasanians in the east, surrendering all claims on Armenia and paying a large indemnity, in order to have his hands free to defend the northern frontier. The late fifth-century Byzantine historian Zosimus wrote of universal confusion and feebleness at the time. ‘Observing that the emperors were unable to defend the state, but neglected all without the walls of Rome, the Goths, the Scythians, the Burgundians, and the Carpi once more plundered the cities of Europe of all that had been left in them, while in another quarter, the Sasanians invaded Asia.’⁸

But if the humiliating treaty with the Sasanians showed the limitations of Rome’s power when faced by another empire, its military capabilities were still superior to those of the Goths and other Germanic tribes. The empire’s northern frontiers were protected by major rivers serving as formidable natural barriers, by networks of fortresses, roads, and supply chains that had been built up over centuries, by warships that patrolled the rivers and seas, and, of course, by a formidable army. Numbering over 300,000 soldiers in total, the Roman army was equipped with better weapons and possessed heavy artillery, and engineering capabilities, that none of the barbarians had at their disposal.

Rome’s problem for now, therefore, was not military but political weakness. Even if some emperors temporarily halted the forces of fragmentation within the empire, the average reign was only three years during the century that followed the millenary. In 293, Diocletian (284–305) attempted to stem the crisis in imperial authority by appointing three co-rulers, each responsible for governing part of the empire. Diocletian’s reign was emblematic of the paradoxes that haunted the Roman Empire. On the one hand, there were no limits to its military ambition. Fortresses were refurbished, the army expanded, and campaigns launched against enemies outside the imperial borders. Foreign delegates were forced to abase themselves in the traditional Persian style, lying flat on the ground in the presence of the emperor. ‘We – protectors of the human race – are agreed that justice must intervene,’ Diocletian proclaimed, ‘so that the long-hoped solution which men could not supply for themselves may, by our foresight, be applied to the general betterment of all.’9 This was still the imperialist ethos at its purest.

On the other hand, Diocletian struggled to cope with social unrest within the empire caused by massive price inflation. The emperor tried his hand at populism, singling out wealthy speculators for blame: ‘Although they each wallow in the greatest riches, with which nations could have been satisfied, they chase after personal allowances and hunt down their chiseling percentages. On their greed the logic of our shared humanity urges us to set a limit.’10 More significant were his catastrophic policies of debasing the coinage, attempting to impose maximum prices, and increasing taxes to pay for the greater military expenditure. Tax revolts broke out all over the empire.

It required a renewed bout of civil war before the strong government and reforms of the Emperor Constantine (306–37) brought a period of relief. To help control the rampant inflation, he introduced a new gold coin, the solidus. He sought to end the blight of religious violence between pagans and Christians by issuing the Edict of Milan in 313, which recognized the right to religious freedom. Although Constantine did not convert to Christianity until he was on his deathbed, his edict is traditionally regarded as the point at which the Roman Empire formally ceased from persecuting Christians and began to adopt the faith. Of similar long-term significance for the empire was Constantine’s decision to move the capital to the strategically situated old Greek city of Byzantium – refounded, in 330, as Constantinople – in order to increase his grip over the restive but wealthy eastern provinces and facilitate the renewed centralization of imperial authority.¹¹

In reality, however, the fourth century saw the Roman Empire increasingly split into western and eastern halves, with rival emperors ruling from Rome and Constantinople. Nevertheless, the empire remained resolved to defend its northern borders, understanding very well that if the barbarians crossed the Rhine and seized the Alpine passes or traversed the Danube and conquered the Hungarian Plain, it would take them a matter of days to march into Central Italy. Although emperors like Constantine and, later, Valentinian I (364–75) could still inflict pulverizing defeats on their barbarian foes, the empire continued to fray. Rome increasingly came to rely on poorly trained barbarian manpower for its defence, both within its legions and as foederati, and on gold to buy peace. The turbulence harmed trade and agriculture in the provinces, while the rich living in the major cities spent like there was no tomorrow. Heavy taxation and tax revolts were the result. When several years of bad weather led to famine, the situation got completely out of hand.

In 356, open war erupted with a confederation of Germanic tribes known as the Alamanni. The neighbouring Salian Franks ultimately had to be granted the land they had settled on around the River Scheldt and accepted as foederati. In 363, Rome agreed on new annual payments of gold to pacify the Sasanians. This time, the senate decided to consult the oracular Sibylline Books. ‘For all the wealth that Rome took from tributary Asia, three times as much shall Asia take from Rome, requiting upon her her cursed arrogance,’ they prophesied. ‘And for all the men who were taken from Asia to go and dwell in Italy, twenty times so many men of Italy shall serve in Asia as penniless slaves.’12 A few years later, civil war broke out at the worst imaginable moment.

The arrival of the Huns on the Pontic-Caspian Steppe had driven the Goths from their homelands and forced them desperately to appeal for permission to cross the Danube into the empire and settle on the southern bank. Rome failed to take the situation seriously. ‘When foreign envoys begged with prayers and protestations that an exiled race [the Goths] might be received on our side of the river,’ wrote the soldier-historian Ammianus, ‘the affair caused more joy than fear.’¹³ The ensuing refusal triggered a major new border war that only ended in 382, when the Goths accepted the status of foederati in return for the right to remain south of the Danube. But still the situation continued to deteriorate. As the chronicler Prosper recorded: ‘A savage storm of barbaric disturbance lay over Italy.’¹⁴

Following the death of the Emperor Theodosius in 395, the empire was formally divided. From now on, there would be two Roman Empires: the Western, with Rome as its capital; and the Eastern, ruled from Constantinople. But even with the empire split in two, at least the appearance of its traditional imperial prestige was maintained. Coins still depicted emperors slaying foreign foes, but were now minted from worthless copper. Triumphal arches were still erected, but the sculptures were often recycled from earlier monuments. On the pedestal of an obelisk in Istanbul, one can still see the Emperor Theodosius proudly looking down on kneeling barbarians. In the tradition of the Pax Romana, Constantine and Theodosius issued laws and protocols governing foreign relations. Writers like the late fourth-century statesman Quintus Aurelius Symmachus recounted how, during peace talks, the emperor was escorted by a host of splendidly equipped cavalry bearing magnificent standards in an attempt to intimidate barbarian opponents.

For most of their diplomacy, though, late Roman emperors relied on embassies – sometimes granted full authority to negotiate on behalf of their imperial masters – and envoys recruited for their familiarity with the language and culture of particular peoples. The senate still formally received foreign delegates and conferred over the taxes required to finance wars. But from the time of Diocletian onwards, most emperors were advised by a sacrum consistorium of senior officials in the imperial administration. After Theodosius, though, Roman diplomacy grew increasingly dysfunctional, with treaties no longer drafted as carefully as they once had been.15

At the end of 406, the northern border of the Western Roman Empire collapsed as the Alamanni, Vandals, and Suevi flooded over the Rhine into northern Gaul. Roman troops were rushed from Britain to meet the threat, leaving its shores undefended against major Saxon raids. ‘The four plagues of sword, famine, pestilence and wild beasts rage[d] everywhere throughout the world,’ recorded the chronicler Hydatius.¹⁶ But worse was still to come. In 408, the Visigoths – those tribes that had been settled on the Danube in 382 – invaded Italy to avenge the massacre there of the families of Gothic foederati fighting in Gaul, whose loyalty had been doubted. As the Visigothic army descended on Rome, attempts to buy it off with vast amounts of tribute and the offer of extravagant honours failed. A long siege followed. ‘Receiving no relief, and all their provisions being consumed, the famine, as might be expected, was succeeded by a pestilence, and all places were filled with dead bodies.’17 It was left to slaves finally to open the gates.

It was the year 410. Rome had fallen to a foreign enemy for the first time in eight centuries. By the time the siege was over the city’s population had halved to 500,000 inhabitants. ‘The brightest light of the whole world is extinguished; indeed the head has been cut from the Roman empire,’ lamented the historian and theologian Jerome.¹⁸ The Visigoths soon abandoned the city laden with booty, but the death struggle of the Western Roman Empire continued for decades as the Huns, the Germanic peoples, and Roman warlords turned its provinces into a battlefield. Finally, in 476, Flavius Odoacer, a Roman general of barbarian stock, deposed the Emperor Romulus Augustulus. Although Odoacer purported to be acting under the auspices of the Eastern emperor, his troops soon proclaimed him king of Italy in his own right. The Western Roman Empire had finally fallen.

Across the Adriatic, however, the Eastern Roman Empire remained a formidable realm that reached from the Danube to the Red Sea. Its capital, Constantinople, contained around 500,000 inhabitants, and was augmented by shiploads of refugees from the Italian Peninsula. Its architecture already rivalled that of Rome. It had palaces, churches, a hippodrome, cisterns, aqueducts, bath houses, and a central square, the Augustaion, in the style of the Roman forum – all protected by mighty walls.

In the watershed year of 476, the Eastern Roman Empire was ruled by Zeno (474–91), and he did everything in his power to uphold ancient glories. He received embassies seated on a high throne and robed in purple. Coins were issued with the diademed ruler spearing a fallen enemy. But he approached the turmoil in the west with a mixture of pomp and pragmatism. Unable to intervene militarily, he attempted to exert authority over Odoacer by granting him the highest honour, the title of patrician. When Odoacer shrugged off Zeno’s imperial overlordship to become king of Italy, the emperor pursued a similar policy with the Gothic king Theoderic, who eventually defeated and murdered Odoacer in 493.

Meanwhile, in 482, Zeno had to address growing fissures between the Christian sects in the Eastern Empire. The Henoticon, his failed attempt to reconcile the opposing Church leaders, opens with an impressive fanfare of titles and epithets – ‘the emperor Caesar Zeno, pious, victorious, triumphant, supreme, ever worshipful Augustus’ – but ends up almost begging for peace and unity. ‘The origin and constitution, the might and invincible defence, of our sovereignty is the only right and true faith.’19 The seeds of a century-long schism between emperor and Church were sown. In 494, Pope Gelasius took the initiative to make the case for the supremacy of papal authority to Zeno’s successor, Anastasius (491–518). ‘There are two things, august emperor, by which this world is chiefly ruled, the consecrated authority of bishops and the royal power,’ he expounded in a letter to Zeno. ‘Of these, the bishops bear a burden which is so much the weightier as they must render an accounting in the divine judgment even for the kings of mankind.’²⁰ The emperor chose quietly to ignore the pope. He pragmatically continued to deploy bishops as diplomats and concentrated on the security of the empire instead.

Anastasius embarked on the refortification of the empire’s eastern frontier, as well as the construction of a wall running from the Sea of Marmara to the Black Sea to protect Constantinople from landward attack. He continued the diplomatic fiction of bestowing imperial honours on various Germanic kings in the West: some were made patricians, others honorary consuls, some even ‘ministers of public amusement’ (tribuni voluptatum). The bishop-historian Gregory of Tours recorded the ceremony when the Frankish king Clovis was made consul after defeating the Goths in 507:

Letters reached Clovis from the Emperor Anastasius to confer the consulate on him. In Saint Martin’s church he stood clad in a purple tunic and the military mantle, and he crowned himself with a diadem. He then rode out on his horse and with his own hand showered gold and silver coins among the people present … From that day on he was called Consul or Augustus.21

Events such as Clovis’s honorary consulship mark the start of an important new chapter in the history of Western Europe: the ambition of Christian kings to resurrect some of the greatness of the Roman Empire and adopt the mantle of its most illustrious rulers – Julius Caesar, Augustus, and the like. Europe’s political order continued to evolve, but the imperial culture of Rome – its legends, its heroes, and its symbols – was preserved.

The Uprising of the Barbarians

In China, the collapse of the Han Dynasty in 220 was followed by an era of confusion, war, and genocide, in which tens of millions died. All traditional values were questioned: most notably, the Seven Sages of the Bamboo Grove suggested alcohol, individualism, free sex, and homosexuality as means of escaping the sorrows of the age.

Three kingdoms dominated the political map of China: the Wei, the Wu, and the Shu. The Wei ruled over most of the North China Plain. Power here had passed from the heirs of the Han Dynasty to warlords of the Cao family, who famously refused the heavenly mandate because becoming emperor, they feared, ‘felt like being cooked on a stove’. To the south, on both sides of the Yangtze, the kings of Wu ruled over a fragmented, shifting realm that stretched all the way to the Red River. The kingdom of Shu ruled over the middle and upper reaches of the Yangtze; its centre of power was the Sichuan Plain, around the modern city of Chengdu. The three kingdoms maintained close trade relations, their different geographies and climates making their markets complementary. The Shu invested heavily in irrigation projects, became successful cotton growers, and traded luxury goods with Central Asia. The Wu had a flourishing agricultural economy, specialized in crafts like green glazed pottery, and built a merchant fleet that sailed to the Korean Peninsula and India. The situation of the Wei was more problematic. They were badly hit by climate change, drought, and depopulation. Wheat, consequently, had to be imported from the south. Under the threat of famine, the Wei were sharp-set and ambitious.

Trade relations between the three kingdoms notwithstanding, the overlapping spheres of interest turned the plains between the Yangtze and the Yellow River into a battleground. An early alliance between the Shu and the Wu did not survive tensions over the city of Jingzhou, a trade hub on the Yangtze. Aware of the turmoil in the Wei kingdom, the Shu launched five major expeditions in six years to conquer it. On each of these occasions, hundreds of thousands of warriors were called to arms. The Shu bribed the Xianbei and Qiang to open a second front, but the Wei held firm, launched a counter-offensive, and conquered the rival capital in 263.

That same year, the Wei Dynasty was overthrown by a warlord called Sima Yan. Sima Yan had no problems with the imperial title: when he seized power from the Wei, he proclaimed that he would avenge the Han Dynasty, a clear aim at the mandate of heaven. In 266, he assumed the title Emperor Wu, formally inaugurating the Western Jin Dynasty. Sima’s eyes now turned to the kingdom of Wu. As the fourteenth-century Romance of the Three Kingdoms – one of the great prose classics of Chinese literature – put it: ‘The towns and walls of Han were in new hands, the hills and streams of Wu would soon follow.’22 He went all out to delegitimize his Wu rival. His advisors told him to move fast: ‘Sun Hua’s tyranny has reached the extreme of violence and cruelty. He can be conquered without a battle. But if Sun Hua should pass from the scene and a capable sovereign come to the throne, your majesty might find it very difficult to conquer the southern land.’²³ To reach the Wu capital across the Yangtze, Sima Yan’s troops reportedly worked for seven years on a fleet of warships. In 280, the Wu surrendered.

Most of the territory of the three kingdoms was reunified, but only in name. Sima Yan was never able fully to assert his power and had to rely on local princes to govern his realm. His successor lost control entirely. The annals describe how the Western Jin state was afflicted by infighting, hailstorms, earthquakes, fires, and the worship of mammon. Plagues of locusts devoured the rice crop; when one official informed the emperor that his people were eating grass because of this, he cynically retorted: ‘Why don’t they eat meat porridge?’24 Writers from that time lambasted the Western Jin emperors for their decadence and immorality. ‘To oppose the rites and injure the teachings [of Confucius] – there is no greater crime than this,’ railed the Jin statesman Bian Kun.²⁵

The mayhem that caused the demise of the Western Jin, as various members of the imperial family competed for the throne, was called the War of the Eight Princes (291–306). Meanwhile, dark clouds had also gathered over the outer borders of the disintegrating dominion of the Western Jin. Just west of the North China Plain, on the plateau of today’s Shanxi Province, a charismatic leader had united many of the tribes of the Xianbei. Continuing merely to raid the plains, he argued, was not an option; they should conquer them once and for all. ‘I have witnessed the past generations to raid and plunder the frontier peoples, and though there was some gain, the loot seized was not worth the cost in casualties, so they again had to call together raids and hostilities,’ he said. ‘The hundred surnames suffer in misery; it is not a long-term tactic.’²⁶

The Xianbei leaned against an open door. Chinese princes, their own resources exhausted, turned once again to the barbarians to aid their internecine struggles. The Shu called on the Qiang and soon had to witness how their new allies captured their capital, Chengdu, in 304. A renegade general of the Western Jin now approached the Xiongnu, who had formerly been tied to the imperial court through marriage alliances and the taking of princely hostages. One of those erstwhile hostages, Liu Yuan, saw the invitation as an opportunity to declare himself emperor of the new state of Han Zhao, march on the great cities of Luoyang and Chang’an, capture the Jin emperor – and make him his butler.

The Xiongnu invasion was cataclysmic. The North China Plain was overrun by tens of thousands of barbarian warriors. ‘Arrows flew like raindrops, and the light of the fires filled the sky.’27 The Western Jin may have mobilized as many as 700,000 soldiers against them; records speak of 100,000 dead soldiers piled on top of one another in a single heap. Famine, disease, and depopulation afflicted the North China Plain. In an act of despair, the Jin wheedled the Xianbei with the titles of duke and prince of Dai. But it was too late, and the Xianbei took advantage of the turmoil to found their own kingdom in 310.

This period, known as the Uprising of the Five Barbarians (304–16), changed the political landscape entirely. The Jin realm had been reduced to the areas south of the Yellow River; henceforth, the dynasty was referred to as the Eastern Jin. The barbarians who took over great swathes of the North China Plain continued to war with local princes and each other with barely a break. In 340, a Xianbei warlord massacred 200,000 people. In 354, an Eastern Jin expedition against the Xianbei cost 40,000 lives. In 383, a war between the Eastern Jin and the Qiang state of Qin left 700,000 casualties. These were just the most noteworthy tragedies.

Exploiting the attritional conflict of the Eastern Jin and the Qin, the Xianbei made another bid for supremacy. This time, they expanded their realm from the middle reaches of the Yellow River down to the Yellow Sea. In 399, a convocation of Xianbei tribes declared their leader Emperor Daowu of the Northern Wei. This new barbarian dynasty aspired to be the equal of the great Chinese dynasties of the past. ‘The mandate was sent down by high heaven,’ Daowu proclaimed. ‘My thoughts are to bring peace to the commoners. I have reverently carried out punishment in accordance with heaven. I have killed Liu Xian, slaughtered [Liu] Wei Chen, pacified the Murong, and settled the central Xia lands … May the deities of heaven and earth bestow their great blessing upon the court of Wei, and forever pacify the four directions.’28 Daowu adopted the traditions of formal consultations with court advisors and of receiving the tribute of lesser rulers and keeping their family members as hostages. Ambassadors were dispatched to the Qin, the Eastern Jin, and the nomadic Rouran tribes.

For more than a century, the Northern Wei ruled over the northern banks of the Yellow River. Their first emperors kept at a distance from the ongoing struggles on the other side of the river to their south and between the nomadic tribes in the north. Most of them embraced Buddhism and pursued a policy of Sinicization. As the Northern Wei court grew ever more luxuriant, they constructed monumental shrines, like the temple caves at Yungang, where finely carved steles and statues of bodhisattvas blend nomadic and Chinese styles. Like previous imperial dynasties, they delegated the defence of the border to tribes on the periphery. Once again, the policy paved the way for ambitious generalissimos. By the turn of the sixth century, the Northern Wei Empire had started to crumble.

Meanwhile, the Eastern Jin had recovered and consolidated their power on the southern banks of the Yellow River. Most emperors were the puppets of military leaders who used the barbarian threat as a pretext to bolster their own status through countless campaigns. The threat of war hung permanently over the southern regions. Yet economically, at least, the Eastern Jin flourished. The leadership was strong enough to keep the realm nominally united, but was too weak to enforce strict control. This environment stimulated private initiative, trade, and agricultural innovation. The Eastern Jin capital, Jiankang, became an artistic and commercial centre with connections as far away as the Indian Ocean. This was the age of inventions like the mobile mill for grinding grains, and the mechanical puppet-theatre; the age when the use of paper for writing became widespread and calligraphy developed into an art form; and the age of great poets like Xie Daoyun:

Looking toward Jiankang city,

the little river flows against the current.

in front, one sees sons killing fathers,

and behind, one sees younger brothers killing older brothers.

These lines were written in around 420. The Eastern Jin Dynasty had just surrendered to the ambitions of their most prominent general, Liu Song. The Jin’s reign was over; its realm ruptured, first into two and then four parts. The Chinese heartland would not be unified again before 581. It was in this context that the teachings of Pure Land Buddhism became very popular. Through enlightenment, adherents could leave behind the world of sorrows for a bird-filled paradise of peace and plenty. The escapism of the Pure Land’s teachings coincided with a particular low in China’s history. The period from the third to the sixth century was characterized by savage political anarchy far more than by imperial order. Even the dynasties of the Western and Eastern Jin were riven with weakness and struggled to control the heartland between the Yangtze and Yellow Rivers.

The Sasanians

Tremors from the twin downfalls of China and Rome were felt across much of the rest of Eurasia. ‘From inside China I have heard worse, not better, news day by day,’ wrote one Silk Road trader. ‘I stay here in Guzang and I do not go hither and thither, and there is no caravan departing from here.’29 Another merchant was astonished by what he had heard. ‘The last emperor, so they say, fled from Luoyang because of the famine, and fire was set to his palace and to the city, and the palace was burnt and the city [destroyed],’ he reported in a letter. ‘Luoyang is no more … and the Indians and the Sogdians there had all died of starvation.’³⁰ At the other end of the Silk Road, in Palestine, Jerome described the sack of Rome in similar terms:

Who would believe that Rome, built up by the conquest of the whole world, had collapsed, that the mother of nations had become also their tomb; that the shores of the whole East, of Egypt, of Africa, which once belonged to the imperial city, were filled with the hosts of her men-servants and maidservants; that we should every day be receiving in this holy Bethlehem men and women who once were noble and abounding in every kind of wealth, but are now reduced to poverty?31

To the Sasanian Empire – the main power lying between China and Rome – the fall of the two other empires was a mixed blessing. The objective of the Sasanians was to build a realm that was stronger and richer than that of their predecessors, the Parthians. Sasanian propagandists damned the Parthians for corruption, tyranny, and incompetence, and applauded the new dynasty for its kindliness, its encouragement of agriculture, and its protection of trade routes against robbers.³²

In the tradition of the Achaemenid Dynasty, the Sasanian rulers claimed the Zoroastrian god Ahuramazda sanctioned their status as ‘kings of kings’ (shahanshah). In the cliff face at Naqsh-e Rustam – the burial place of the Achaemenids – a rock carving of the first Sasanian king, Ardashir I, portrays him on a horse trampling the last Parthian ruler. ‘This is the figure of the Mazda-worshipping Lord Ardashir, shahanshah of Persia, who is descended from the gods.’ The message was spelled out in Persian, Parthian, and Greek, highlighting the heterogeneity of the Sasanian Empire. The Parthians had sought to handle the challenges such diversity posed to their rule with a policy of tolerance. Initially, the Sasanians followed suit; but as they became more successful, their attitudes hardened.

Benefiting from the weakness of Rome, Ardashir’s son, Shapur I (240–70), overran Syria in 250, avenging an earlier defeat. According to Shapur:

When at first we had become established in the empire, Gordian Caesar raised in all of the Roman Empire a force from the Goth and German realms and marched on Babylonia … Gordian Caesar was killed and the Roman force was destroyed. And the Romans made Philip Caesar. Then Philip Caesar came to us for terms, and to ransom their lives, gave us 500,000 denars, and became tributary to us … And Caesar lied again and did wrong to Armenia. Then we attacked the Roman Empire and annihilated at Barbalissos a Roman force of 60,000, and Syria and the environs of Syria we burned, ruined and pillaged all.33

The victories of Shapur I demonstrated the Sasanian Empire’s ascendancy over Rome. Although a new treaty ceded the Sasanians control over a large part of Armenia in 271, it was not enough. In 315, Shapur II (309–79) invaded Armenia to ‘reconquer what had belonged to his ancestors’. He declared Zoroastrianism the official religion of the Sasanian Empire. Its forced imposition led to the persecution of Jews, Christians, and Buddhists. Religious repression was partly a way to strengthen royal prestige, and partly a ploy against Rome and Constantinople, which by now had embraced Christianity. Rome retaliated: ‘Our task is to wipe out a most pernicious people, on whose swords the blood of our kin is not yet dry.’34 But the Sasanians prevailed. With the Roman threat waning, Sasanian attention moved to the east. Shapur II mounted several campaigns in Central Asia, which brought the Sasanians into competition with the Huns. To help counter the Hun threat, the Sasanians attempted to cultivate the friendship of the Xianbei, sending them envoys and a gift of tame elephants.

From the fifth century onwards, wars with the Huns along both the northern and eastern borders of the Sasanian Empire became more frequent. The Sasanian kings prevailed and used the opportunity provided by this victory to try to force concessions from the Eastern Roman Empire, which had been more seriously afflicted by Hunnic invasions. Constantinople proved a tougher military rival than the Huns, though. So the most King Bahram V could extract was a treaty that recognized the rights of Zoroastrians in the Eastern Roman Empire and Christians under the Sasanians. In 445, Ctesiphon and Constantinople signed a new deal: the Sasanians would be paid for defending Anatolia from incursions by the Huns through the eastern mountain passes.

At its peak, the Sasanian Empire stretched from the Euphrates to the Hindu Kush and from the Aral Sea to the Indian Ocean. Its riches impressed even Chinese envoys. The capital, Ctesiphon, had over 100,000 households, they reported. As for the rest of the empire: ‘The land is fairly level and produces gold, silver, coral, amber, very fine pearls, vitreous ware and glass; crystals, diamonds, iron, copper, cinnabar, mercury; damask, embroidery, cotton, carpeting and tapestry. The climate is very hot and families keep ice in their houses.’³⁵ The reception of foreign dignitaries at the court was overwhelming. The Sasanians built immense vaulted brick halls. Their weight required the palace walls beneath them to look like fortresses. The impression of sturdiness was something the kings cultivated for themselves through heroic triumphal reliefs and martial statues, both in the tradition of the Achaemenids. But it was counterbalanced by the dazzling refinement of Sasanian tapestry, jewellery, glazed tiles, frescoes, poetry, and music.

The Sasanians pursued an aggressive policy to control trade along both the overland Silk Road and its maritime equivalent in the Indian Ocean. Ports and settlements were built near strategic chokepoints, like the Bab-el-Mandeb and the Strait of Hormuz, which connect the Red Sea and the Persian Gulf to the Indian Ocean. Even if trade was damaged by the turmoil in Rome and China, the Silk Road continued to serve markets like Egypt, the Levant, India, and Southeast Asia.

Merchants and envoys entering the Sasanian Empire had to announce themselves to the marzbans, noblemen who administered and guarded the border provinces. They were also part of the much larger martial aristocracy that furnished the empire’s chief military asset: heavily armoured cavalry. As this suggests, Sasanian society was rigidly stratified. The Denkard, a compendium of Zoroastrian beliefs, warned: ‘Know that the decadence of states begins when one permits the subjects to practice other than their traditional occupations.’36 In fact, the empire does seem to have been plagued by social unrest at the end of the fifth century. A radical preacher named Mazdak attracted widespread support for a social revolution – involving land reform, subsidies for the poor, and the abolition of the privileges of conservative clerics – in order to reverse growing inequality. At the same time, tensions between the court and nobility, not least among the marzbans, escalated into open conflict. The nadir was reached after 458, when pretenders to the imperial throne first brought the Hephthalite Huns into the empire from which they had so long been kept at bay. In 475, the Hun presence was powerful enough to force the king to pay tribute. Now ‘chaos and famine ruled and women were shared by all’.37

The Guptas

About forty days’ travel east from the Indus River border of the Sasanian Empire lay a small kingdom in the Ganges Valley. This was the homeland of the Guptas. Their early history is not well documented, but evidence of a marriage between the dynasty’s founder, Chandragupta (320–35), and a princess of the powerful Magadha kingdom attests to their growing prominence. Through conquest and alliances, Chandragupta incorporated dozens of other small kingdoms along the Ganges. Like the Sasanian rulers, he titled himself ‘king of kings’ (maharajadhiraja). Sixty years later, the Gupta realm stretched from the Indus to the Bay of Bengal. It was the first time in centuries, after the Maurya dynasty, that a native Indian dynasty had been so powerful. The Guptas profited from the downfall of the Kushan Empire and the fragmentation that followed, but their rise was also facilitated by the smooth succession of Chandragupta’s son, the potent king Samudragupta (335–80).

Samudragupta, like his father, was a capable strategist and commander. Many neighbouring rulers were coaxed into matrimonial alliances. Others were bound by a ritual called the Ashwamedha yajna, whereby a ruler acknowledged his submission by accepting the gift of a horse. Those who refused the horse faced a formidable war machine, consisting of elephants, armoured cavalry, archers who used humidity-resistant steel bows, and a well-equipped riverine navy that allowed the Guptas to project their power along the banks of the Ganges and inland from coastal waters.38 Because northern India was a patchwork of statelets and tribes, the Guptas’ expansion was hard to stop. It was aided by the alliance they maintained throughout this period with the Vakataka kingdom, the dominant state on the northern Deccan Plateau.

The Gupta heartland was governed directly by the king, who was supported by a cabinet and an assembly, the sabha.³⁹ Vassal kings paid tribute and sent their sons to the Gupta court. Relations with tribes in the forests and kingdoms in the northern mountains were much less formalized. The ancient Arthashastra of Kautilya resurfaced as a practical guide to diplomacy. It inspired much of the work of the influential Gupta writer Kamandaka, who asserted that the anarchic nature of politics meant the ideal form of rule was paternal despotism (nitisara). A good king should always prioritize national interests, maintain a modern army – yet prevent it from depleting the treasury or causing the neglect of agriculture – and never expect foreign alliances to last. Kamandaka also made the case for just wars, arguing that force should be used only after the failure of strategies such as conciliation (sama), bribery (dana), or sowing dissension (bheda).

Gupta kingship had much in common with that of the Maurya, as expressed not only in the Arthashastra but also in the edicts of Ashoka. The king was expected to uphold the rule of law (dandaniti) and refrain from harshness (krodha), unjust punishment, and the unwarranted seizure of property. As for more personal qualities, he should be well versed in the arts, music, science, and archery (dhanurveda), and not inclined to indulge in women, liquor, or gambling. Inscriptions paired the king’s merits as a warrior with qualities like wisdom, calmness, compassion, refinement, and sensitivity. Despite the fact that, in the imperial hierarchy of the Gupta, the gods came first, then the law, and only then the monarch, the Gupta kings made sure their majesty was apparent to all. Their coins were emblazoned with images of them slaying tigers or human foes. Rock carvings proclaimed the Gupta monarch to be the digvijaya – the conqueror of the four quarters of the world.

The age of the Guptas witnessed a cultural and intellectual florescence. Sculptors melded Greek and Asian influences into works of exceptional sensuality. Vatsyayana compiled his great erotic treatise, the Kama Sutra. Scientists posited that the earth had to be round. Mathematicians developed the numerical system that we still use today. One of the ‘nine gems’ (navarathnas) of the Gupta court was the Sanskrit poet and dramatist Kalidasa, whose writings open a window directly on to its splendour and sensuality. Travellers who came from far afield – such as the Buddhist monk Fa-Hien at the beginning of the fifth century – marvelled at the wealth, luxury, and bounty of the Gupta kingdom.40

But the wisdom and majesty of the Gupta kings was soon challenged by the Hephthalite Huns. The Hephthalites had seized the rich trading cities and agricultural zones of the Amu Darya (Oxus) and Ferghana valleys, the heart of the former Bactrian kingdom. Under their aegis, the region flourished as a centre of commercial and cultural exchange, and as an important destination for Buddhist pilgrims, who flocked to its monasteries and religious schools.41 Now the prospect of monopolizing the caravan routes through the Hindu Kush brought them into conflict with the Guptas, who had similar ambitions of their own. It led to a series of major wars, and caused havoc across the northwestern regions of the Gupta Empire.

At first, the Guptas prevailed. The king had ‘accomplished his programme of conquests’, it was stated. ‘He can now devote himself to the tasks of peace and leave the sword for the flute as worshipper of Vishnu and his consort, Lakshmi.’⁴² But the victory came at a price. Through force of circumstance, kings no longer adhered to the precepts of Kamandaka’s statecraft, draining the treasury to finance the army, and levying new taxes that brought a halt to economic growth. By the end of the fifth century, a combination of economic weakness, unrest in the border kingdoms, and fresh attacks by the Hephthalite Huns brought the empire to its knees – and the Hephthalites to dominate, albeit briefly, much of Central Asia and northern India.

Killing Beasts for the Buddha

Until its collapse, the Gupta Empire served as the main hub of the trade system that had emerged during the previous centuries. Via the passes of the Hindu Kush, it traded with the Sasanians and Central Asia; via the Indian Ocean with China, Southeast Asia, Sri Lanka, the Arabian Peninsula, East Africa, and the Eastern Roman Empire. The expansion of trade coincided with the expansion of cities and kingdoms outside the traditional centres of power.43 One of them was the kingdom of Funan. An inscription called it a ‘realm of mud’, because it had emerged from the marshy Mekong Delta.⁴⁴ The Chinese records described it as the place where East and West met, because its ports connected the South China Sea with the Indian Ocean. They were served by sailors from Malaysia, who perfected their skills in navigating between the hundreds of islands of the Southeast Asian Archipelago.⁴⁵ They transported gems, pearls, sandalwood, gum, and spices. In the third century, Funan seems to have paid tribute to the Eastern Jin, exchanged frequent diplomatic missions with them, and supplied them with significant numbers of trained elephants. The Chinese sources also indicated that five lesser kings in present-day Myanmar and Laos acknowledged Funan as overlord.

Chinese travellers marvelled at the abundance of luxurious goods in Southeast Asia, not only in Funan, but also in kingdoms like Taruma, in modern Indonesia, and Langkasuka, in modern Malaysia. Even though territories in the region specialized in the production of different wares, competition for trade and the control of sea lanes was merciless. The same held true in Southern Asia. The Guptas relentlessly tried to control trade; and after their downfall, competition continued between other kingdoms. The Pandyan Kingdom on the southeastern coast of India vied with Sri Lankan kings for domination over commerce in the Palk Strait. The rich natural resources of Sri Lanka made it an immense and tempting prize. In the fifth century, the Pandyans invaded the island in 429 and ruled it for several decades. In 455, they were pushed out, but this episode of oppression stirred Sri Lankan nationalism. The Mahavamsa, a historical and religious epic from the period, equated the killing of invaders with the killing of wild beasts: it was the will of the Buddha that the island’s inhabitants should defend its independent sovereignty. ‘Unbelievers and men of evil life’ were ‘not more to be esteemed than beasts,’ it read. ‘But as for thee, you will bring glory to the doctrine of the Buddha in manifold ways; therefore cast away care from your heart, O ruler of men!’46

Northeast Asia too saw the spread of Buddhism, trade, and migration. With China losing its imperial lustre, Manchuria, the Korean Peninsula, the East China Sea, and the Japanese Archipelago were transformed into a playground for several ambitious lesser powers: for example, the Yan – of Xianbei origin, but claiming the heavenly mandate – or the kingdoms of Baekje and Silla in the south of the Korean Peninsula. In Japan, the Yamato controlled most of Honshu, the largest of the archipelago’s islands. Their king governed from a peripatetic court, and functioned more as the leader of a clan federation than a formal monarch.

The most powerful polity, however, was the Goguryeo kingdom in the Korean Peninsula. By 300, it had defeated its rivals in the Manchurian Plains. It embraced Buddhism and its arts reveal both Chinese and nomadic influences.⁴⁷ But it was also a martial society. For centuries, Goguryeo had competed with the Xianbei, Silla, and Baekje by means of both diplomacy and open war. Evidence for the scale of the turmoil is provided by the Stele of King Gwanggaeto (391–413), which credited the famed Goguryeo monarch with the unification of the Three Kingdoms of Korea, the defeat of the nomads, the construction of a chain of fortresses in Manchuria, and the imposition of tribute on smaller neighbours. In just one decade, he fought no fewer than ten major battles.48

Much further to the west, a similar regional conflict loomed over the Red Sea. With the downfall of the Western Roman Empire in the late fifth century and inability of the Eastern Roman Empire to project the same degree of influence as the earlier Roman Empire, two trading states rushed to fill the void: the Jewish kingdom of Himyar, in present-day Yemen, and the Christian kingdom of Aksum, in present-day Ethiopia. Himyar had already conquered neighbouring states like Hadhramaut and the ancient kingdom of Saba (Sheba), both famed for their production of frankincense. Aksum had grown rich from the export of ivory, elephants, and cotton. The influential third-century Sasanian prophet Mani regarded Aksum as one of the four great powers of the age, along with Rome, the Sasanian Empire, and China. Aksum maintained relations with Constantinople and copied its pomp. A Byzantine visitor reported how the Aksumite monarch received his guests on a golden chariot drawn by four elephants. The mid-fourth century Ezana Stone recorded how one ruler defeated neighbouring states to become the ‘king of kings’: ‘After having subjected their kings, I ordered them to pay a tribute for their territory and to leave in peace navigation and land traffic.’⁴⁹ His attack on Himyar was described as a holy war in revenge for killing Christian envoys and as the reclamation of ancestral territory. Campaigns were also staged against the Nubians, after they had robbed Aksum’s envoys and refused demands for submission.

The Blending of Nations

The period between 250 and 500 unfolded like one long crisis of empire, at least for the Mediterranean, Western Europe, and China. Although the collapses of the Roman and Han Empires occurred at different times, they were remarkably similar. Both, at first, became hollowed-out states: they possessed garrisons and fortresses around their perimeters, but increasingly polarized societies within. Their seemingly hard outer shells weakened, however, as garrisons could no longer be paid and barbarians had to be incorporated within the empire. Even so, the pressure from the outside continued to mount, caused by the lure of the wealth that lay tantalizingly within reach and by the impact of environmental change and mass migration. When the borders finally gave way, the result was cataclysmic.

The decline of Han China and imperial Rome, therefore, was not a case of comparative shifts in power – of strong, prosperous states simply being overtaken by more dynamic ones. In both China and Rome, the imperial crisis sparked anarchy, hardship, famine, and population decline. The effect would be much the same if a foreign power invaded Washington today and forced its citizens to relocate to Mexico, or if contemporary Beijing was sacked and millions forced to flee to Korea. The fate of the Han and Roman Empires should also remind us that the barbarian invaders of today are often the citizens of tomorrow.

This blending of nations was not a smooth process. The relocations of people were often brutally violent events. At the same time, though, the assimilating pull of the old civilizations often proved very powerful. The barbarians that invaded China embraced the heavenly mandate with the same eagerness as the Frankish king Clovis cloaked himself in Roman consular purple. This was also true in the more newly established regimes in the Middle East and Southern Asia. The Sasanians adopted the imperial traditions of the great Achaemenid kings – and carved their portraits in the rocks beside those of their Persian forebears – with the same keenness as the Gupta rulers embraced the teachings of Kautilya and Ashoka.

This era witnessed another major geopolitical change: the growing importance of the Indian Ocean and the northern steppes as conduits between peoples. Trade in the Indian Ocean had certainly existed before, but from this period there is strong evidence of growing and more sustained connectivity. The Gupta Empire acted as an interface between the Middle East and Southeast Asia, where new trading kingdoms became prominent. The same was true for the northern steppes beyond the Caspian and Black Seas. The Scythians and other nomadic peoples had travelled over this highway of grass long before, but the speed with which the Huns moved along this corridor, and the magnitude of their migrations, were probably unprecedented. The continental Silk Road, revived after the Sasanians reunified much of the Middle East and Persia, thus now formed the central strand of a tripartite system of east–west trade routes: to the south was a maritime network spanning the Indian Ocean from the Strait of Malacca to the Strait of Hormuz and the Bab-el-Mandeb; to the north, an overland transit zone across the steppes. Greater knowledge of the magnitude of the Eastern Hemisphere was gained both from expeditions of trade and from expeditions of conquest; and both stimulated the desire to push the boundaries of understanding ever onwards.