The museum in the Chinese city of Luoyang possesses one of the world’s finest collections of Tang Dynasty tomb sculptures. These small, playful terracotta figures portray elegant dancers, fierce warriors, and also prosperous merchants perched on top of the sort of heavily laden camels that regularly made the arduous trek along the Silk Road. The period in which they were made – the second half of the eighth century CE – is still considered a golden age not just of art but also of trade. Travellers described the crowded centres of commerce, filled with merchants from distant regions, thriving like true metropolises, and gleaming with ‘pearls and jade like a fairyland’ as ‘thousands of lanterns shone over the clear, dark blue sky’.1

The Tang emperors were not the only rulers to encourage trade; so did their chief peers, the Frankish and Byzantine emperors, and the caliphs of the Abbasid Dynasty, who had succeeded the Umayyads. Numerous accounts – especially from the Abbasid Caliphate – attest to the increasing scope of the trans-Eurasian trade. ‘There is the Tigris, to put us into trade contact with lands as far as China, and to bring us all that the seas yield as well as the foodstuffs of Mesopotamia,’ recorded the ninth-century Persian polymath al-Tabari. ‘And there is the Euphrates to transport to us all that Syria, al-Raqqah, and their regions have to offer.’2 The tenth-century Arab geographer al-Muqadassi added: ‘Caravans from Egypt and China will come by way of the desert, and all types of products will reach you from China via the sea, and from the realm of the Greeks and from al-Mawsil [Mosul] via the Tigris.’³

Men like al-Tabari and al-Muqadassi were cosmopolitans who highlighted the benefits of trade and the wonders of distant countries. To itinerant scholars like these, as well as to explorers and traders, the world literally became more open. ‘Among the discoveries of this age of ours,’ reported the tenth-century Persian scholar Abu Zayd al-Sirafi, ‘is the previously unsuspected fact that the ocean on to which the Sea of China and India opens is connected to the Mediterranean Sea.’⁴ As a result, in the eighth and ninth centuries new atlases and encyclopaedias began to be made of the Indian Ocean and the land routes to China, like Ibn Khordadbeh’s Book of Roads and Provinces, or Jia Dan’s famously detailed and vast map of China’s western hinterland.

The first adherents of Islam were merchants: although the faith prohibited usury, it did not forbid profits earned through trade. To facilitate their increasingly long-distance ventures, Islamic merchants began to evolve a sophisticated commercial infrastructure. Contemporary sources record the widespread use of debt arrangements or payment instructions (suftajahs), so that traders did not need to carry cash. There was the qirad, a kind of joint-stock agreement in which multiple investors entrusted capital to a trader in the expectation of making profit from his activities.⁵ The caliphate established trade zones (funduqs), rest houses, and relay stations for courier services, and financed the construction of bridges to improve routes like the ancient King’s Highway and Royal Road. Trading with infidels was not an issue either: the Abbasids dealt profitably with the Franks, the Byzantine Empire, Tang China, and countless lesser powers. In turn, Constantinople reduced trade taxes and subsidized the building of merchant ships.6 Far to the northwest, the Frankish court of Charlemagne at Aachen marvelled at the exotic goods and the copies of ancient Greek and Roman writings supplied to the palace school from all around the Middle East, to the point that his reign has traditionally been described as the Carolingian Renaissance.

But political obstacles to this nascent globalism remained. The whole Silk Road, we learn from Abu Zayd al-Sirafi, was lined with fortresses, dominating valleys, commanding passages over rivers, or looming over ports. They secured trade against robbery, but they also taxed and controlled it. On the Tang-administered section of the Silk Road, east of the Tian Shan, al-Sirafi recounted how guard posts blocked the road and traders needed to obtain permits to proceed with their goods.⁷ At one stage, the Tang imposed a ban on dealing with ‘the darker races’, a measure primarily aimed at the Central Asian kingdoms.⁸ Trade suffered from wars between the major powers, but also from political turmoil within states. ‘The trading voyages to China were abandoned and the country itself was ruined,’ wrote al-Sirafi about the downfall of the Tang. ‘The Chinese placed undue impositions on merchants [and] seized their property by force.’⁹

Most importantly, the trade in luxuries and its accompanying cosmopolitanism were enjoyed by only a fraction of the people. There were, however, some improvements to their lot. In Europe, the climate became warmer. Iron horseshoes, the heavy plough, and the horse collar all made farmers’ lives a little easier. But existence remained a daily fight against the wilderness. ‘Wherever he spent the night he cut down trees … and made a circular fence for the protection of his ass, so that it would not be devoured by the wild beasts that were numerous there,’ we read in the life of a wandering hermit in what is now Germany.10 An abbot in northern France warned of the state of constant lawlessness: ‘Brigandage is committed in the realm of our King Charles with impunity and there is nothing surer or more constant than violence and rapine.’¹¹ Similarly gloomy portraits were painted in the monastic annals of that time. Wherever the population grew, it sheltered as much as possible in the lee of fortress or city walls. This was the case not just in Europe but throughout most of the Eastern Hemisphere.

Abundant Goods and Honest People

In 734, the Tang emperor Xuanzong (712–56) wrote to the Yamato ruler in Japan informing him of the fate of three of the latter’s ambassadors, who had failed to return home. A storm had blown their ship off course and wrecked it on the coast of Linyi, in present-day Vietnam, where they were robbed and sold into slavery. The emperor offered words of consolation: ‘Linyi and other countries in the area pay tribute to China. I have already instructed the protector-general at Annan [Hanoi] to issue an edict to their rulers, ordering them to escort the Japanese diplomats to the protectorate, should any of them be spotted. I have also instructed the protector-general to comfort and send the Japanese home.’12

Diplomacy clearly remained a risky business; but Xuanzong’s missive also reveals the sense of superiority that underlay his display of magnanimity. Such condescension was not reserved only for Japanese rulers. Xuanzong also referred to the khagan of the Turks as his son, for example, and refused a peace proposal from the Tibetan king because the latter addressed him as an equal. Precedence mattered, and the emperor – backed by an army of more than 600,000 men – was able to insist on it.

Xuanzong’s reign was called ‘the splendid age of original opening’, an era of confidence, peace, and prosperity.¹³ Amid the bustle of the capital, Chang’an, lay peaceful imperial gardens where exotic birds and animals gathered from across the realm reflected the natural harmony bestowed by the empire. This was the classical period of the Chinese arts. It was Xuanzong who founded the first Chinese opera school, known as the Pear Garden. He supported poets like Li Bo, and painters like Zhou Fang and Zhang Xuan, who created masterpieces celebrating the splendour and elegance of court life in return. Artisans blended techniques and styles from across Asia into sophisticated and sumptuous works of terracotta, gold, jade, and silk.

Xuanzong himself sought to excel in the arts of governance. Although he approved of the Confucian respect for tradition, he was a Taoist. He departed from legalist and Confucian principles to make the Tang legal code fairer. He also encouraged farming in order to replenish the state’s granaries; built new locks on the Grand Canal, which ran between the River Yangtze and the Yellow River; and took various other steps to promote trade both inside and across the border. ‘The Yellow River is clear and calm,’ the Tang’s historian recorded. ‘The country enjoys peace and harmony. Goods are abundant and people are honest. Kingdoms like Anxi have submitted to, and were ruled by, the Tang … Everywhere enjoyed bumper harvests and the people were prosperous. Young men in the prime of life carried no weapons. No one would pick up and keep other people’s property on the road.’14

To all appearances, this was still the heyday of the Tang Dynasty. But it was soon shown to be little more than a splendid façade. Natural disasters emptied the granaries. Famine and violence forced the emperor to evacuate the overpopulated capital. ‘Inside rich men’s doors, wine and meat went to waste,’ wrote one of the era’s greatest poets, Du Fu; ‘while frozen corpses littered the roadside.’¹⁵ Revolts broke out in northeast China, forcing the emperor to withdraw troops from the western border. The region’s powers were quick to exploit the situation: the Tibetans broke their peace agreement; the nomadic Uighurs strengthened their hold on the region of modern Mongolia; and bands of the nomadic Khitan people raided across the border. The remaining Chinese forces were too feeble to defeat the armies of the Islamic Caliphate at the Battle of the Talas River in 751.

Worse was still to come. In 755, the warlord An Lushan took advantage of the hardship in the north to rebel. The uprising became one of the bloodiest episodes in Chinese history, costing tens of millions of lives. ‘Each man of you has a bow and a quiver at his belt,’ Du Fu wrote; ‘And the sound of their sorrow goes up to the clouds.’16 In 756, Emperor Xuanzong was forced into retirement. Subsequent emperors restored a degree of stability, but could only do so by calling on the Uighurs and mercenaries from the caliphate to check Tibetan aggression. In 758, Arab and Persian pirates burned the city of Guangzhou; its port was not rebuilt for five decades. In 762, when the future emperor Dezong was dispatched to the Uighurs to affirm an alliance, they had the effrontery to try and make him dance.

This experience led Emperor Dezong (779–805) to reconsider relations with the Uighurs as soon as he ascended the throne. Advisors were invited to craft a strategy. But while some favoured an alliance with Tibet to resist the Uighurs, others considered Tibet to be the main rival and proposed attacking it. ‘When the Tibetans are weak, they ask for an alliance, when they are strong, they invade,’ one general counselled; ‘now they have penetrated deep into our territory and they ask for a treaty, they certainly want to cheat us.’¹⁷ The emperor nevertheless decided to forge ahead with negotiations. The Tibetans, however, declined to proceed as long as they were referred to as ‘subjects’. They got their way, and an alliance was concluded in 783. When rebellion broke out in China a year later, Tibetan troops helped patrol the streets of Chang’an. But as soon as the capital had been secured, tensions between the Tang and Tibet rekindled. This time, China resolved to check the Tibetans by forging a grand alliance with the Uighurs and the caliphate. ‘I think it would be best that Your Majesty build rapport with Uyghur in the north, Yunnan in the south, and [the] Arab Empire and Tianzhu in the west,’ an imperial official advised. ‘By doing this, we could isolate the Tibetans.’18 An alliance was established in 789, but did not last long, so that insecurity in the west continued to grow.

Meanwhile, the empire also fragmented domestically. When Emperor Dezong attempted a series of fiscal reforms to relieve the poor, he only exacerbated the problem. The existing taxation system, whereby a household’s liabilities were based on the number of its members, had caused a rural exodus. But the new system, in which taxation was calculated on a family’s wealth and assets rather than headcount, created an even more polarized society. Dezong’s death was followed by a period of economic mismanagement, corruption, and instability. A number of taxes, including those on salt, were abolished, but this expedited the decline of the power of the imperial court. The difficulties were aggravated by climate change. ‘A vast expanse of desert is covered with ice of a thousand feet,’ wrote the poet Cen Shen, as a prolonged period of exceptionally cold weather caused bad harvests and renewed conflicts with the nomadic peoples in the north.¹⁹ Emperor Xuanzong (846–59) temporarily restored order, but under his heirs the Tang Empire continued to decay economically and to disintegrate politically. When the wealthiest landlords resisted paying their dues, Emperor Xizong (873–88) reinstated the salt taxes. This, however, led to smuggling, crime, and further unrest. By the time the last Tang emperor was poisoned by a usurper in 907, the dynasty had ruled in little more than name for years.

The Tang collapse was followed by more than half a century of anarchy, an era known as ‘the Five Dynasties and Ten Kingdoms’ period (907–60). In reality, there were many more contenders, few of whom survived for more than a couple of decades. Fighting was incessant and accelerated the development of weapons like flamethrowers and the long zhanmadao sword. The north in particular suffered from depopulation. Cities became impoverished and the canal system that supported the food supply broke down. The country was rendered defenceless against foreign intrusion. The Tibetans, the Uighurs, and the Khitan now all commanded large territories inside what had been the Tang realm. Even Chinese kingdoms during this period, such as the Later Han, the Later Tang, and the Later Jin, were ruled by strongmen of Central Asian stock. The writer Wang Renyu decried how the quarrelling Chinese kingdoms of his day fell prey to barbarian rulers. The Later Jin, he recounted, ‘lost control, while traitorous ministers sold out their country. Fierce armies and valiant warriors were helplessly surrendered, the common people were slaughtered one by one … Since the beginning of the world there had never been disorder like this.’20

By far the most formidable power during this period was the Khitan federation of tribes from the Mongolian and Manchurian steppes. In 907, its ruler crowned himself Emperor Taizu of the Liao Dynasty. He disparaged the Chinese for their decadence, laughed at their numerous uprisings, and expected Chinese kings – whom he addressed as his sons – to meet him in person and accede to his territorial demands. ‘That my son in China had come to such troubles, I already knew,’ he told one unfortunate envoy. ‘But I had heard reports that this son kept two thousand women in his palace, and a thousand musicians, that he spent his days hawking and running his hunting hounds, that he was wallowing in drink and sex; he had no concern for his people.’²¹ When Taizu died in 926, the Liao Empire extended as far south as the Yellow River.

For a brief moment, the balance of power in East Asia had shifted to the north, where the plains and hills of Manchuria became an arena of power politics. On the coastal plains that bend around the Yellow and Bohai Seas, the Liao locked horns with the smaller kingdoms that controlled the southern banks of the Yellow River, such as the Later Zhou. In 954, the Later Zhou met a Liao-backed coalition in the Battle of Gaoping. The records explain that the northern coalition underestimated its rival and attempted to fight in the teeth of an intense southerly gale. It was decisively defeated, and its southward expansion stalled. Soon after the battle, in 960, a Zhou general founded one of China’s most commercially minded dynasties: the Song. Although the Liao continued to control the area north of the Yellow River, the first Song emperors, Taizu and Taizong, increased their own domains at the expense of the other kingdoms to the river’s south. But when, in 979, the Song attacked the Northern Han state, which had succeeded the Later Han and straddled the Yellow River, the Liao attempted to come to its defence. The rivalry between the Liao and the Song would continue for another 150 years.

Meanwhile, in the Korean Peninsula, the Silla kingdom – which had been the leading state since it had cast off the Tang dependency in the early eighth century – was overthrown in 936 by the recently founded kingdom of Goryeo, which considered itself the heir of Goguryeo. We do not know how exactly Goryeo prevailed, although Silla had long been in political decline. But with the advent of Goryeo, state building in Korea reached a new level: its achievement in unifying the peninsula still serves as an ideal of Korean unity today. The first king of Goryeo, Taejo, came from a wealthy mercantile family, and he had clear ideas about the preservation of his dominion. His principles of statecraft included devotion to the Buddha, the maintenance of probity at court, light taxation, openness to criticism, and guarding the country’s independence.

Taejo remained constantly alert to potential threats, both internal and external. ‘I only fear that my successors will give way to their passions and greed and destroy the principle of government,’ he admitted shortly before his death, and then warned: ‘Since our country shares borders with savage nations, always beware of the danger of their invasions.’22 That danger would eventually become pressing. Initially, the Goryeo kingdom was separated from the Liao by the nomadic Jurchen, and the two agreed to join forces to prevent the Jurchen from raiding their towns. But after the Liao dealt a major defeat to the Jurchen in 991, they were left facing Goryeo across the Yalu River – and both felt entitled to establish a foothold on the other’s side. ‘Since your country does not take care of the people’s needs,’ pronounced a Liao general trying to justify aggressive action, ‘we solemnly execute Heaven’s punishment on its behalf.’²³

Warriors of the Buddha

In Southeast Asia, the ninth century saw new dynasties establish the outlines of nations and cultures that are still visible today in Cambodia, Vietnam, Indonesia, and Myanmar. The region’s inhospitable geography of numerous rivers and forested mountains formed intractable barriers to overland communication – but this merely encouraged the forging of seaborne connections that tied its peoples together through the exchange of trade, the sharing of Hindu and Buddhist beliefs, and the creation of a common artistic language still visible in the remains of temples, palaces, and objects from the age. This same geography gave the region its immense strategic significance as the chief conduit for maritime commerce between China and India. The straits of Malacca and Sunda became crucial transit points, promoting the establishment of significant trading ports that, in turn, helped fuel the development of kingdoms, especially in Malaysia, Sumatra, and Java.

But trade, faith, and progress also bred war. The kingdom of Srivijaya, which emerged in the late seventh century on the island of Sumatra – strategically positioned between the straits of Malacca and Sunda – was the first to try and control the flow of trade by dominating these chokepoints.24 It curried favour with China by dispatching tributary missions and offering pepper, turtles, pearls, and ivory in exchange for iron, ceramics, and silk. It proposed to the northern Indian Pala Dynasty that it build a Buddhist temple on its territory and it offered to donate gold to temples in southern Indian cities. Its king approached the caliphate, announcing that he was eager to trade and asking the caliph to ‘send to me someone who might teach me Islam and instruct me in its Laws’.²⁵ Srivijaya tried to prevent others from siphoning off traffic by itself conquering the Malayan Peninsula and attacking trade cities in the kingdoms of Khmer and Champa in modern Cambodia and Vietnam. Chinese sources report that ships were forced by Srivijaya to moor in the Strait of Malacca, so that they could be monitored and taxed.

Competition over commerce came with a religious dimension. In accordance with Buddhist doctrines, Srivijayan kings in the late seventh century embarked on a siddhayatra. What was meant to be a quest for spiritual enlightenment in reality involved the conquest of trade cities. Srivijayan troops destroyed Hindu temples on the Malayan Peninsula and erected Buddhist monasteries in their stead. Initially, Srivijaya extended its influence on the neighbouring island of Java through dynastic alliances. But by the ninth century, the two island states were locked in an increasingly bitter struggle for regional supremacy that simmered on into the next millennium.

On the continent, meanwhile, the threat of Srivijaya encouraged the unification of the Khmer under King Jayavarman II at the beginning of the ninth century. He relocated the Khmer political centre to the north, where it was safer for Srivijayan warships. In the process, the Khmer moved against the small kingdom of Lavo and turned it into a puppet state protecting their western border. Over the course of the next two centuries, the successors of Jayavarman steadily extended the bounds of the Khmer Empire and increased its wealth. At the end of the tenth century, civil war between rival claimants to the Khmer throne sucked in regional powers from as far afield as India.

As well as conflict, there was also intense diplomatic interaction between the states of Southeast Asia. Kings employed religion to propagate their influence, erecting temples and monuments, and using priests and monks as envoys. Nevertheless, warfare at some level was almost incessant, although armies numbered only a few thousand soldiers – closer in scale to contemporary European warfare than to the huge battles fought in China or India. This situation was to some degree both the cause and the effect of the emergence of the first significant monarchical states in the region during this period. To these nascent dynasties, status was almost everything. The king of Java was the ‘saviour of the universe’ and the ‘protector of Buddhism’, for example, while the Srivijayan monarch styled himself ‘king of the ocean lands’. ‘Victory be to this king of Srivijaya,’ one inscription proclaims, ‘the glory of whose rule is worshipped by the neighbouring rulers, and who has been created by the creator of the universe as if intent on making firm the best of religions.’26 The reality of Southeast Asian politics, however, was a state of anarchy existing beneath the overlapping shadows of Indian and Chinese spheres of influence.

India’s Four Kingdom Period

‘This prince’s heart is sanctified with courtship, since he recognizes the merits of others. His pride is concealed under genuine modesty.’²⁷ Thus the eighth-century poet-dramatist Bhavabhuti described the qualities of a ruler in his Exploits of a Great Hero. In the tradition of the ancient epics, this play about the early life of the Hindu deity Rama is a struggle between the ideal form of justice championed by the priestly upper caste of Brahmins and the evil caused by corrupt kings and the devilish priests who supported them. Bhavabhuti’s plays are steeped in cruelty from which nobody could escape, not even women and small children.

India’s population during the time of Bhavabhuti was probably around 60 million. Most of it was distributed across the Indo-Gangetic Plain where, much like the rest of the world, the vast majority lived in rural settlements. We can gain an impression of the daily struggles they faced from the large number of carved ‘hero stones’ that still survive from the period. These commemorate men and women who were important to their communities: a warrior who gave his life to defend his village; a husband who protected his family from robbers; a farmer who killed a leopard trying to eat his cattle. Increasingly large numbers of people, though, were also to be found clustered along the coasts of India, where trading cities thrived and connected the rich hinterland with export markets as far away as Europe and China.

The lives of city dwellers and peasants alike in this era were overshadowed by one major event: the struggle between the Palas, the Rashtrakutas, the Pratiharas, and the Islamic Caliphate over the fertile plains of the north. The conflict was one of competing religions as much as states: the caliphate of course was Muslim, but the Palas were Buddhists, the Pratiharas were Hindus, and the Rashtrakutas were Jainists. It seems that their respective areas of strength prevented the advantage from swinging decisively and permanently in favour of one of them; the Palas possessed the largest number of both war elephants and warships, the Rashtrakutas had the most infantry, the Pratiharas fielded the best cavalry.

The Pala Dynasty had its origins in around 750 on the banks of the Padma River, the most important branch of the lower Ganges, in present-day Bangladesh. A group of tribal leaders granted the title of ‘protector’ (pala) to King Gopala, hoping that this would terminate a period of internecine conflict in the region. In the words of the inscription recording the event: ‘To put an end to the state of affairs similar to what happens among fishes, people made the glorious Gopala, the crest jewel of the heads of kings, take the hand of Lakshmi, the goddess of fortune.’28 Another inscription praised Gopala for ‘releasing the war elephants’ against the neighbouring tribes and states.²⁹ Clearly the Palas valued foreign conquest as much as domestic stability.

At about the same time as the emergence of the Palas, much of the Deccan Plateau and southern coasts of India fell under the control of the Rashtrakuta king Dantidurga. He was also the first of his dynasty to hold the mahadana (great gift) ceremony: to celebrate the king’s birth from the golden womb of the divine universe, his weight in bullion was distributed to the needy. Similarly, the northwest of the Indo-Gangetic Plain was united by the first Pratihara king, Nagabhata, a descendant of the Huns, after he defeated an invasion by the forces of the caliphate and ‘retrieved the earth from calamity’.³⁰ Despite this setback, the caliphate continued to try and force its way into northern India, as it had done ever since it reached the banks of the Indus in the late seventh century. This was the logical next step, given its control of the northern coastal plains of the Arabian Sea and the routes through the mountain ranges that gave on to the Indus Valley. The prize was not just to bring the word of God to the infidel, but also to seize the agricultural and mercantile riches of a land famed both for its bounty and as the recipient of the goods that flowed down from the Silk Road through the passes of the Karakoram to the Indian Ocean.

The struggle between these four powers ensued for almost two centuries. The Palas struck first, when King Dharmapala launched a sacred war over the Buddhist shrines in the north. His main target, however, was Kannauj, a prosperous trading city right in the centre of the Indo-Gangetic Plain. He defeated both the Pratiharas and the Rashtrakutas and, in around the year 800, his supremacy was recognized at an imperial durbar (assembly), where he appointed a puppet king to reign over the middle reaches of the Ganges. ‘With a sign of his gracefully moved eye-brows he installed the illustrious king of Kanyakubja, who readily was accepted by the Bhôja, Matsya, Madra, Kuru, Yadu, Yavana, Avanti, Gandhâra and Kira kings, bowing down respectfully with their diadems trembling, and for whom his own golden coronation jar was lifted up by the delighted elders of Panchâla.’31

But Dharmapala failed to secure the region. These outwardly subservient kings soon rebelled, called in the Pratiharas, and collectively defeated the Palas. This was followed by a new attack by the Rashtrakutas, who prevailed over both the Palas and Pratiharas. In around 850, the Pratihara king Mihira Bhoja reignited hostilities with a series of offensives. The Pratiharas retained their influence in the northwest of the Indian subcontinent for about sixty years and were then defeated by the Rashtrakutas, who were now receiving assistance from the Arabs. By the turn of the ninth century, however, all three kingdoms began to suffer from internal unrest. Its causes are unclear, but the situation was instantly exploited by the Ghaznavids, a breakaway kingdom from the caliphate. In 1018, the city of Kannauj was captured not by an Indian dynasty, but by the Muslim ruler Mahmud of Ghazni.

This long-running contest for control of northern India was accompanied by great efforts by the participants to spread their cultural and religious influence. The Palas built Buddhist monasteries that became centres of learning. The Rashtrakuta capital, Manyakheta, was the residence of important Jain intellectuals, such as the mathematician Mahaviracharya and the poets Sri Ponna and Adikavi Pampa. The Hindu Pratiharas left awe-inspiring temple complexes, such as those at Osian, in modern Rajasthan, which are embellished with carvings that remain among the finest in the history of Indian art. Despite the fighting, the main powers also still traded with one another: their economies were largely complementary in terms of luxury goods. Everything – the art, the wars, the magnificent royal courts – was financed by heavy taxes on trade, land, salt, and minerals. Even if there is no definitive evidence for it, the burden must have fallen mainly on the shoulders of ordinary people, the local craftsmen and small farmers.

The Abbasid Takeover

In around 714, the Umayyad caliph Walid I ordered the construction of a new palace-city. Unusually, the site chosen was an arid and remote spot, two days away from his capital, Damascus. Anjar, as the place was called, came to boast spectacular colonnades, grand squares, and exquisitely carved marble. Here, in seclusion, the caliph intended to live in peace and devote himself to poetry, wine, and women. Walid, like the caliphs that came after him, brooked no disobedience of his wishes. These Umayyads upset traditional Islamic political thinking by asserting that they were the equals of the Prophet Muhammad.32 Toleration of different Islamic opinions, let alone of completely different religions, gave way to a form of totalitarianism.

The schism between reality and the new doctrine of obedience, however, could not have been larger. The Umayyad Dynasty was crumbling. In the east, Persian subjects had become tired of the crackdown on Zoroastrianism, the influx of Arab migrants, heavy taxes exacted to support garrison towns, and the growing sense of Arab racial superiority that locked others out from government. In 719, a predominantly Shia resistance movement, the Hashimiyya, sprang up in the remote valleys of Central Asia. Its leaders claimed to be the heirs of the Banu Hashim clan to which Muhammad had belonged. They condemned the Umayyad caliphs as illegitimate and promised liberation from their tyranny. While preaching Shia Islam, they also incorporated Zoroastrian elements and struck a conciliatory tone towards Jews, Sunni, and Christians. Fuelled by the wider resentment in Persia and Mesopotamia, the Hashimiyya Movement spread like wildfire.

In 743, civil war erupted in Syria. When the Umayyad caliph was killed near Damascus, the victor ordered his head ‘to be put on a lance, to have wine sprinkled on it and to be paraded around the city, announcing that “this is the head of the wine-lover.” ’³³ Thousands of camels carried the royal treasury out of the city.³⁴ There were ‘beatings, pillaging, and violation of women in front of their husbands’, the astrologer monk Theophilus of Edessa recorded.35 Meanwhile, the ranks of the Hashimiyya Movement continued to swell and they descended on to the Mesopotamian plain. By now, the ‘wearers-in-black’ had formed an alliance with an influential Shia clan which claimed descent from the Prophet Muhammad’s youngest uncle, Abbas, and which came to be known as the Abbasids.

In 749, the Middle East was struck by an earthquake that destroyed several cities. To the chroniclers, the ominous message was clear: a new era of anarchy had begun. ‘Eyewitnesses affirmed that in Mesopotamia the ground was split along two miles and that out of the chasm there came up an animal like a mule, quite spotless, that spoke in a human voice and announced the incursion of a certain nation from the deserts against the Arabs.’³⁶ Disorder gripped the world not only in the sphere of civil affairs, Theophilus of Edessa wrote. There was fighting and bloodshed everywhere. In 750, an army of over 100,000 Umayyad troops was defeated by predominantly Shia warriors lead by the Abbasid chieftain Abu al-Abbas al-Saffah in the Battle of the Zab, in the north of what is now Iraq. After this victory, al-Saffah proclaimed himself the first caliph of the Abbasid Dynasty.

The downfall of the Umayyad Caliphate triggered a heated debate between scholars, jurists, and clerics on how the civil order of Islamic society should be maintained. All sides agreed that the Quran and the sayings of the Prophet remained the principle source of law, that the umma should be preserved, and that Islam should continue to be spread. But thereafter there was little consensus as to precisely how those fundamental principles should be translated into practice.

One of the ideas originating at this time which had the greatest long-term impact was the notion that all non-Muslim societies should be thought of as belonging collectively to a ‘house of war’, or Dar al-Harb. First proposed by the famous jurist Abu Hanifa, the concept and its ramifications were fleshed out in more detail by his disciple al-Shaybani in his Introduction to the Law of Nations. Al-Shaybani’s treatise did not question whether jihad should be waged against infidels – they resided in the ‘house of war’, after all – but it did propose a framework for how jihad should be waged. Those refusing to accept the teachings of Islam should be fought by any means, and killed, pillaged, or enslaved, although a degree of mercy, on some occasions, could be shown to women, children, and the elderly.37 But al-Shaybani also showed a degree of pragmatism, accepting that in certain circumstances peace treaties could be negotiated with the peoples of the Dar al-Harb, their merchants and envoys granted safe conduct, and trade conducted with them.

These views were later confirmed by the prominent eleventh-century jurist al-Mawardi, whose Ordinances of Government is one of Islam’s most comprehensive works on justice, politics, and war. Al-Mawardi’s priority is defence: the caliph’s primary duty is to protect the lands of the believers – the Dar al-Islam, or ‘house of peace’ – and the holy sanctuaries. ‘There is no benefit to a leaderless people when disorder reigns, and they will never have a leader if the ignorant amongst them leads.’³⁸ Only once such order has been achieved should the caliph turn to fulfilling the obligations of jihad. Like al-Shaybani, al-Mawardi declared that the inhabitants of the Dar al-Harb should be given the opportunity to sue for peace in return for paying tribute. Their lands would then become part of the ‘house of conciliation’, or Dar al-Sulh. ‘It is not permitted to resume the jihad against them as long as they make the payments.’39 If the infidels resisted, any means could be used ‘to harry them from their houses and to inflict damage on them day and night, by fighting and burning’.⁴⁰ Women and children, however, should still not be killed, but merely enslaved.

To symbolize the zealousness of their allegiance to the Prophet, the Abbasid Dynasty took black as its official colour: black for its banners, black even for the tunic of its messengers. Black had been the colour of the flags borne by Muhammad’s army in the decisive victory that led to the capture of Mecca over a century earlier. Coins hailed the caliph as the ‘prince of believers’ and ‘servant of god’. New caliphs swore oaths at their accession. ‘It is necessary to have a leader to keep religion and justice on the right road, protect the rights of all Muslims, and lead campaigns against pagan enemies,’ one of them proclaimed. ‘God, in His compassion and wisdom … has spared human beings the trouble of having to go in search of their leaders. He has designated them Himself and honored them by making them descendants of the Prophet.’⁴¹ ‘May Allah be a witness if he let me be Amir al-Mu’minin, and made me a caliph,’ another vowed; ‘and if he did make me a caliph then I would follow his word and Way of living, and that of the Prophet’s, and would transmit that to my citizens, and I would not kill people or destroy places randomly, and I would not take someone’s home or pillage their country, and be careful in making my decisions.’⁴²

The first Abbasid caliphs recentralized power at the same time as they expanded the Islamic empire. Although they were severely critical of the Umayyads for the laxness of their rule, they did adopt several of the most important administrative tools of their predecessors, such as divans (ministries) and qadis (judges in sharia courts), as well as introducing significant innovations, such as the role of wazir (vizier, or chief advisor). The caliphate now consisted of core provinces under direct rule, like Mesopotamia, Syria, Egypt, and Western Iran, and peripheral ones, like Armenia, North Africa, and Central Asia. Governors in the former provinces were often members of the royal family, rotated frequently, and monitored by the barid – a form of intelligence agency that reported directly to the caliph. In the latter provinces, military governors were deployed.

In 762, the second Abbasid caliph, al-Mansur (754–75), relocated the capital to the newly constructed city of Baghdad, officially known as Madinat al-Salam, or the ‘city of peace’. Under al-Mansur, Baghdad became a centre of the arts, sciences, and philosophy. He dispatched envoys to Constantinople to request copies of the Greek philosophers for his library, the ‘house of wisdom’. With the reign of Harun al-Rashid (786–809), the dynasty reached its peak. Harun is most widely remembered now for his presence in the entirely fictional Book of One Thousand and One Nights, which nostalgically portrayed his caliphate as a golden age of Islamic civilization. Court poets at the time, however, were also effusive in their praises:

‘Through Harun, the light has shone forth in every region,

and the straight path has become established by the justness of his conduct.

a leader who has ordered his affairs through the attention to God’s requirements …

People’s eyes are unable to endure the brilliance of his face.43

Perhaps such panegyrics were not entirely heartfelt. As al-Tabari slyly observed: ‘The poets sang his praises, for which he rewarded them profusely.’⁴⁴

Harun had gained precious experience as a prince in campaigns against the Byzantine Empire. One of his first deeds as caliph, therefore, was to fortify the Byzantine border and to behead dissident governors in the frontier provinces.⁴⁵ But despite such vigilance, it was under his rule that the still youthful Abbasid Caliphate started to weaken. Unrest in Syria, Egypt, and Persia never stopped. In Spain, the emirate of Córdoba recognized the new dynasty, but remained the last defiant outpost of Umayyad rule. In 788, the Idrisid Dynasty established itself in Morocco. In 793, the governor of Iran broke away. It required an expedition of 50,000 troops to restore order. Harun’s death was followed by yet more disorder. By around 813, Baghdad was utterly lawless. Mutinous soldiers ‘used to band together, go up to a man, seize his son and carry him off, and nothing could be done to stop them’, wrote al-Tabari. ‘There was no government authority which could restrain them … because the government authority itself depended on them.’⁴⁶ By 820, the caliphate had lost control over Syria and large swathes of its Central Asian territories.

An examination of the caliphate’s treasury reveals a drop of 50 per cent in the ninth century.⁴⁷ Wars with the Byzantine Empire helped drain the coffers. But it was also partly due to the neglect of agricultural production in Mesopotamia and the failure to collect taxes from Egypt and the eastern provinces. The more caliphs’ incomes dropped, the greater the effort to levy new taxes – and the greater the unrest that followed. The caliphs became increasingly dependent on military men to maintain their rule, but they had to be rewarded with land. In 869, a massive slave uprising broke out near Basra, on the Persian Gulf. The caliphate had been importing large numbers of slaves for infrastructure works, farming, and the infantry. The Zanj Rebellion cost hundreds of thousands of lives. Young men became the slaves of slaves, women their concubines. ‘I could hear their uproar, crying out “There is no God but Allah” as they were put to the sword,’ recalled one eyewitness. The Zanj leader in Basra ‘burned down the congregational mosque; he also burned the harbor from the cable to the bridge, the fire destroying all before it, including people, animals, goods, and merchandise … Anyone with some money was tortured to extract it and then killed, but anyone who was poor was killed straightaway.’48 The rebellion lived on for another fourteen years before it was finally extinguished.

Meanwhile, the Abbasid Caliphate continued to fragment. Between 868 and 905, the Tulunids took control of Egypt and most of the Levant. Around 909, the Fatimid Dynasty started their expansion from Algeria. In the 930s, the Buyid Dynasty began to seize Persia and parts of Mesopotamia – including, in 945, Baghdad. But as the Islamic world tore itself apart, another small fringe power from the steppes of Central Asia was readying to strike.

The European Hellhole

The Abbasid Empire contained over 50 million inhabitants at its peak. With over a million citizens, Baghdad was the world’s largest city.49 By comparison, the Frankish Empire under Charlemagne numbered around 20 million people, the Byzantine Empire around 10 million, the Bulgarian Empire 2 million, and Umayyad Spain even fewer.⁵⁰ In Europe, the period saw the slow emergence of rich commercial cities: Córdoba, Seville, Palermo, the city states of the Italian Peninsula, Cologne, Mainz, Regensburg, Paris, London. Apart from a dozen or so, none had more than 20,000 inhabitants. The Arabic cities of Palermo and Córdoba and the Byzantine capital of Constantinople were the only cities with more than a quarter of a million residents.

Between the late eighth century and the early ninth century, Northern and Western Europe briefly became the focus of great power politics. The event with the most lasting significance was the founding of the first true empire in Western Europe since the fall of Rome. It was created by the Frankish king Charlemagne (768–814) out of his victories over the Frisians, the Saxons, the Bavarians, the Avars, and the Lombards; and it received formal acknowledgement of its status in Rome on Christmas Day, 800, when the pope crowned him ‘emperor of the Romans’. Charlemagne’s ‘Holy Roman Empire’ – as it is known to posterity – was built on the successes of his Carolingian predecessors. He inherited a realm much larger than those of potential rivals, so that he could muster more financial resources and troops against his enemies to the south and east. His cavalry, in particular, was a further strength. Shock attacks by heavily armoured horsemen – the distant forebears of the medieval knight – proved decisive in overcoming infantry; but mounted troops were equally valuable for clearing the territory around hostile cities, so that they could be starved into submission.51

Strong cavalry was also the most obvious military advantage held by one of the period’s other important emergent powers, the pagan Bulgarian Empire of Khan Krum (795–814). Even though far less is known about Krum than Charlemagne, it is clear that he conquered a realm that encompassed large parts of Eastern Europe, benefiting from the weakness of the Avars due to the Frankish campaigns against them, and from the exhaustion of the Byzantine Empire as a result of its wars with the Abbasids. The other major new European state was the Umayyad emirate of Córdoba, in Spain, which came into being in 756 when the former province of the caliphate refused to acknowledge the Abbasid Dynasty.

The competition between Franks, Bulgars, Arabs, and Byzantines – between pagans, Christians, and Muslims – led to some remarkable alliances that overrode the claims of faith. Although the Franks took pride in their reputation as the defenders of Christendom, they were still prepared to form an alliance with the Abbasids to fight the Umayyads of Córdoba. Charlemagne addressed Harun al-Rashid in letters as his ‘brother’. The caliph reciprocated with the gift of an elephant named Abul-Abbas, hunting dogs, horses, and swords of the finest steel. The Franks and the Abbasids shared another rival in the Byzantine Empire. The conquest of the Lombard kingdom in Italy in 774 brought the Franks into direct competition with Constantinople, which still retained some territorial interests in the Italian Peninsula. The Byzantines felt threatened by the presence of Frankish ships in the Adriatic Sea, and were especially displeased that Charlemagne’s protection of Rome had earned him the pope’s favour and honours.

Competition over the Adriatic – and particularly the increasingly autonomous but still formally Byzantine city of Venice, whose strategic situation was already obvious – caused relations between the Carolingians and Byzantines to deteriorate fast. Charlemagne’s daughter, who had been betrothed to the Byzantine imperial heir, was kept at her father’s court in Aachen.52 Charlemagne also dispatched envoys to Khan Krum to propose a joint offensive against the Avars, and he imposed an embargo on selling arms to the latter. ‘Let them not bring arms or breastplates to sell.’⁵³ After the Avars had been brought to their knees, Krum turned his cavalry south, against the Byzantine Empire. He defeated its army, killed its emperor, and turned his skull into a drinking cup. It was only when Krum stood poised to take Constantinople that the desperate Byzantines sued for peace. For years, diplomats travelled between the two courts, before a peace treaty was finally sealed in 815. Subsequently, the two states even organized a joint mission to demarcate the border.

European diplomacy at that time was mainly conducted by prelates. Their main task was to read the letters of their monarchs, not to negotiate. It took an envoy about fifty days to travel the dangerous road between Aachen and Constantinople. When the tired travellers finally arrived at their destination, they were sometimes treated poorly. One envoy lamented about his frugal reception by a Byzantine bishop. ‘It is written, “God is love,” and in that grace he is entirely lacking.’54 On other occasions, the envoys appear to have been overwhelmed by what they encountered. Charlemagne’s biographer Einhard, who was an official at his court, recounted how envoys prostrated themselves humbly before the emperor’s cook, having mistaken him for the emperor himself.⁵⁵ Einhard also described the official reception that followed:

The emperor was clad in gems and gold and glittered like the sun at its rising: and round about him stood, as it were the chivalry of heaven, three young men, his sons, who have since been made partners in the kingdom; his daughters and their mother decorated with wisdom and beauty as well as with pearls; leaders of the Church, unsurpassed in dignity and virtue; abbots distinguished for their high birth and their sanctity; nobles, like Joshua when he appeared in the camp of Gilgal; and an army like that which drove back the Syrians and Assyrians out of Samaria.⁵⁶

The deaths of Charlemagne and Khan Krum in 814, together with the infighting that continued to ravage the Abbasid Caliphate after the death of Harun al-Rashid in 809, raised the prospect of a period of respite for Constantinople. Before long, however, the Byzantine Empire found itself hard pressed to contend with sustained attacks by Islamic troops from North Africa on its possessions in Sicily.⁵⁷ In 840, a Byzantine delegation was sent to Córdoba to propose an alliance against those interlopers, as well as against the Abbasids, and to suggest the emirate reclaim its ancestral lands in the Levant. The Bulgars, meanwhile, were preoccupied with fighting Charlemagne’s successor, Louis the Pious, and it was not until the 830s that they began to exert pressure again on the Byzantine border in the Balkans. The ability of the Carolingian Empire to encroach on the Byzantine sphere of influence was further diminished by the civil war which erupted after the death of Louis the Pious in 840, and by the Treaty of Verdun which brought it to an end in 843. The price of peace was the dismemberment of the Frankish Empire into three separate states – West, Middle, and East Francia.

Once again, Europe slumped into a morass of anarchy, as rulers struggled and failed to maintain their authority. It was a dreadful situation. Foreign travellers like the early tenth-century Abbasid envoy Ibn Fadlan described Europe as rich in trees, fruit, and honey, but nevertheless a cold, violent, and filthy hellhole.58 From the early ninth century, Western Europe began to fall victim to the scourge of the Vikings. The annals of the West Frankish abbey of St Bertin, for example, recorded how in 841: ‘Danish pirates sailed down the Channel and attacked Rouen, plundered the town with pillage, fire and sword, slaughtered or took captive the monks and the rest of the population.’⁵⁹ Worse was to follow: in 845, St Bertin fell victim to the vast Viking fleet that rowed up the Seine to attack Paris. ‘The heathen broke in upon the Christians at many points,’ the annals of the West Frankish abbey of Xanten noted in its entry for that year. ‘Yet owing to his indolence Charles [the Frankish king] agreed to give them many thousand pounds of gold and silver if they would leave Gaul and this they did. Nevertheless the cloisters of most of the saints were destroyed and many of the Christians were led away captive.’60 At the same time, local warlords also fought each other without restraint, afflicting their subjects with ‘acts of devastation, burning, rape, sacrilege, and blasphemy’.⁶¹

Such havoc confirmed many Christians’ view that the year 1000 heralded Doomsday, the Day of Judgment. ‘Then will end the tyranny of kings and the injustice and rapine of reeves and their cunning and unjust judgments and wiles,’ wrote one English monk. ‘Then shall those who rejoiced and were glad in this life groan and lament. Then shall their mead, wine, and beer be turned into thirst for them.’⁶² Instead of eternal salvation or damnation, however, the dawn of the eleventh century merely rose on a Europe that was still recovering from the downfall of the Roman Empire, and remained politically fragmented, economically backward, and thinly populated. Yet it also revealed the skeleton of a geopolitical order that, at first glance, is suddenly more recognizable to modern eyes: the Germanic states of the Holy Roman Empire, kingdoms of England, France, Poland, and Hungary – and the seemingly eternal twin poles of the papacy in Rome and the Byzantine Empire.

The Mirror of History

Let us try to draw some conclusions about the history of the first thousand years of the common era – the subject of the last four chapters – focusing, once again, primarily on the Eastern Hemisphere, and on five main aspects: the distribution of power; political organization; the nature of interactions between polities, including the causes of war and peace; the interaction of people and their environment; and the nature of thinking about world politics.

Throughout the first millennium, power still depended heavily on the size of populations. People meant hands; hands meant farmers, artisans, and fighters. Numbers mattered. But there were other factors that made societies more efficient in accumulating power. Mobility, for instance, allowed for large-scale trade, exploitation of resources, and conquest. The Romans led the way here. Their connective power was enhanced by an unequalled combination of transport capabilities on land: for example, standardized roads, courier services, and highly mobile legions. They also possessed a powerful navy and a large merchant fleet.

The most successful polities had it all: a large taxable population, economic cohesion, military strength, good administration, and capable leaders. The presence of the holy trinity of natural resources – water, fertile soil, and a temperate climate – was no longer sufficient by itself. Egypt and Mesopotamia, for instance, not only ceased to exist as independent polities, their populations barely grew. The North China Plain remained vital for China’s agricultural production, but the northern plateaus and the southern hills became equally important. In South Asia, the centre of power extended out from the Indo-Gangetic Plain to encompass the trade routes in the north and the coastal cities in the south.

The political order in the first millennium was dominated by a series of empires, each of which controlled tens of millions of subjects at its height. One of the largest and most successful was Rome, which combined dominance over the Mediterranean with dominance over a significant portion of Europe north of the Alps. Just as its rise had reshaped the political map of the Eastern Hemisphere, so its collapse in the fifth century defined the outlook of subsequent geopolitics. The downfall of the Han Empire in China in the third century, followed as it was by almost four centuries of political fragmentation, was of similar consequence. In both cases, the power vacuum that ensued was filled by peoples that were previously considered barbarians: the Qiang, the Xianbei, and the Xiongnu in China, the Germanic peoples in Europe.

The vast space between Rome and China was filled by other important polities. In the Middle East, the Parthian Empire gave way to the Sasanian, which was succeeded in turn by the Islamic Caliphate of the Umayyads, with its power base in the Levant, and then the Islamic Caliphate of the Abbasids, with its centre in Baghdad. South Asia, meanwhile, was dominated by a series of empires centred variously in the northwest around the Indus, such as the Kushans; in the south on the Deccan Plateau, such as the Rashtrakutas; and in the northeast along the middle and lower Ganges, such as the Guptas, who were unique in the extent of their command over the subcontinent.

By the turn of the tenth century, however, most of the Eastern Hemisphere’s imperial order – the Tang, the Abbasids, the Carolingians, the Byzantines – appeared to be disintegrating. For a moment, it seemed as if there was no longer a place for great empires. Centrifugal forces prevailed; power fragmented. Across the entire globe, from Yucatán – the cradle of the Maya culture – through Europe and the Middle East, to the Japanese Archipelago, periods of violent upheaval were as common as periods of imperial stability.

Wars were fought for a handful of reasons that recurred time and again. Most obviously, they were fought because states had the power and the ambition to do so. In seventh-century China, for example, the Tang emperor Taizong was so convinced of his strength that he launched wars of conquest in all directions. In Central America, Teotihuacan pushed further and further into the Maya heartland because it realized the balance of power had tilted decisively in its favour. The motivations for such wars were often dressed up in ideas of justice or righteousness. The Sasanian kings of the third century, for instance, presented their wars with Rome as attempts to avenge earlier wrongs and reclaim what had been seized from their ancestors. Many imperial powers possessed a version of the doctrine that underlay the Pax Romana: that is, their conquests brought peace and prosperity to benighted realms. Indeed, in China, barbarian peoples like the Xianbei became as avid in using the heavenly mandate to justify their own wars of conquest as the states of the North China Plain had originally been in using it to legitimize attempts to conquer them.

Conversely, many wars occurred because states’ weaknesses invited foreign intervention. In some cases, rebellion and unrest led rulers or pretenders to invite foreign powers to help restore order – only to find that their erstwhile allies created even greater instability. This happened, for example, with the Sasanian Empire and the Hephthalite Huns in the fifth century, and the enfeebled Tang Dynasty and Tibet in the late eighth. Elsewhere, imperial overstretch so weakened the sinews of the state that empires crumbled from within: in the late ninth century, for instance, the breakdown of the overburdened and exhausted Abbasid Caliphate saw the emergence of new states in North Africa, Persia, and the Levant. And sometimes it was the effect of environmental factors that forced desperate peoples into conflict. Perhaps the most obvious example of this was the climate change that drove the Xiongnu and Huns from their native lands, setting in motion the chain reaction of wars and migrations that culminated with the downfall of the Western Roman Empire at the hands of the Germanic peoples in 476.

Another major cause of war was a version of what theorists of international relations refer to as the ‘security dilemma’: namely, that the efforts made by a state to strengthen its security causes its neighbour to reciprocate, thereby creating tensions that ultimately lead to war. In an era when frontiers and spheres of influence were often only loosely defined, keeping potential enemies as far away as possible from one’s heartlands was the best form of security. This factor led to recurrent tensions between the states of the North China Plain and their neighbours in the Korean Peninsula, the northern and western plateaus, and the southern hills. It also led to numerous clashes between the Roman and Byzantine Empires on the one hand and the Parthians and Sasanians on the other over the Armenian Highlands and the northern Mesopotamian plain.

A further catalyst for rivalry and confrontation was the desire to control the proceeds of trade. Many contested areas were important conduits for commerce: the eternal tussle for supremacy in Central Asia, for example, was in essence a struggle to monopolize the streams of wealth channelled by the Silk Road across most of the landmass of Eurasia. And when, partly in an attempt to bypass the obstructions on the overland route, long-distance maritime trade developed across the Indian Ocean, another theatre of conflict was born. Witness, for example, the efforts of the Sasanian Empire and the kingdom of Srivijaya to control the strategic chokepoints that lay at their respective ends of the Indian Ocean.

Finally, there was religion. Although religious differences did not necessarily prevent polities from forging ties of friendship and cooperation, at some time or another holy wars were fought by every faith and conviction – Hindus, Buddhists, Confucians, Taoists, Christians, Muslims, and pagans. The Buddhist kings of Srivijaya portrayed their late seventh-century wars of conquest as siddhayatras, or quests for spiritual enlightenment. The Christian kingdom of Aksum, in East Africa, attacked the Jewish kingdom Himyar, in the Arabian Peninsula, in revenge for the latter killing its envoys. The eighth-century Carolingian state mobilized troops under the holy cross in order to justify its wars against the Muslims to the south and the pagan peoples to its east. Religious differences could even cause adherents of the same faith to fight each other. In the eighth century, the Abbasids argued they were seizing the caliphate from the Umayyad Dynasty at least in part because of the latter’s lack of true Islamic fervour. Only a couple of decades later, the papacy called on the Carolingians to protect its leadership of Christianity from the interference of the Lombard kingdom and, less obviously, the Byzantine Empire.

Undoubtedly, the ideal of peace remained a constant and fervent aspiration throughout the first millennium. But, more often than not, thinking about the nature of world politics was remarkably unfettered by sentiment or illusion. The interaction of states, cultures, and religions was characterized by struggle. Islamic scholars drew a very clear distinction between the community of believers (the umma) and the world of non-believers which formed the ‘house of war’ (Dar al-Harb). The teachings of the New Testament were far less belligerent; but, from the fourth century, most Byzantine theologians argued that Christian rulers were duty-bound to defend their subjects with force against pagan attacks. The influential Gupta theorist Kamandaka cautioned rulers always to be prepared because their alliances would never last. The Tang emperor Taizong warned that the state was dangerously weakened when men were allowed to roam at their ease and forget about war. One of the most accomplished rulers in Chinese history, Taizong, had another piece of wise advice for future leaders: study history thoroughly. ‘Use history as a mirror so as to know the rise and fall of the dynasties.’63