The Religious Landscape Before the Mongol Conquests

In the early 13th century, Asia was a patchwork of faiths and philosophies. Buddhism, which had originated in India centuries earlier, had spread along the Silk Road into Central Asia, China, Korea, and Japan. In Tibet, Vajrayana Buddhism was flourishing under the patronage of local kings and monastic institutions. Meanwhile, Islam had become the dominant religion in Persia, Central Asia, and parts of the Indian subcontinent, carried by traders and Sufi missionaries. Christianity—particularly the Nestorian (Church of the East) and Syriac traditions—had established communities as far east as China, while Manichaeism and Zoroastrianism still survived in pockets. The Mongol heartland itself was home to shamanistic and animistic beliefs, with no centralized religious authority. Conflicts between these faiths were not uncommon; for example, in the Khwarezmian Empire, tensions between Sunni and Shia Muslims occasionally erupted, and Buddhist monasteries in Central Asia had suffered destruction during earlier Turkic invasions.

Before Genghis Khan united the Mongol tribes in 1206, the region lacked the political stability needed for sustained religious exchange. Trade routes were disrupted by wars between the Song Dynasty, the Jin Dynasty, the Khwarezmian Empire, and various steppe confederations. Religious communities often existed in isolation, and the transmission of ideas was slow and risky. This fragmented landscape set the stage for a dramatic transformation once the Mongols created the largest contiguous land empire in history.

Genghis Khan's Religious Policies and Their Implementation

A Pragmatic Approach to Faith

Genghis Khan was not a religious reformer, but he was a shrewd pragmatist. He understood that his empire would need the cooperation of diverse populations—Buddhists, Muslims, Christians, Taoists, and others—to function effectively. Accordingly, he issued a series of decrees (yassa) that, among other things, guaranteed religious freedom throughout his domains. The principle was simple: all religions were to be tolerated as long as their adherents remained loyal to Mongol rule. This was not a matter of personal belief—Genghis himself remained a shamanist—but a calculated policy to reduce resistance and encourage the submission of conquered peoples.

Historical accounts, such as those recorded by the Persian historian Juvayni, note that Genghis Khan exempted religious leaders from taxes and military service, and forbade the destruction of places of worship. This policy was extended to Buddhists, Muslims, Christians, and Taoist priests alike. For example, after the conquest of the Khwarezmian Empire (1219–1221), the Mongols spared Muslim scholars and imams, even as they destroyed the region's military infrastructure. Similarly, in northern China, the Mongol invasion initially targeted Confucian officials, but Daoist and Buddhist monasteries were often left untouched—provided they submitted to Mongol authority.

The Role of Successors: Ögedei, Möngke, and Kublai Khan

Genghis Khan's successors institutionalized this tolerance. Ögedei Khan (r. 1229–1241) ordered the construction of Buddhist temples in Karakorum, the Mongol capital, alongside mosques and churches. Möngke Khan (r. 1251–1259) actively engaged in theological debates, inviting Buddhist monks, Christian missionaries, and Muslim scholars to his court to discuss philosophy. This created an atmosphere of intellectual exchange that was rare in the medieval world.

Under Kublai Khan (r. 1260–1294), who founded the Yuan Dynasty in China, religious policy became even more systematic. Kublai personally converted to Tibetan Buddhism, but he did not impose it on his subjects. Instead, he maintained a multi-faith court: Buddhist monks, Nestorian Christians, Muslim astrologers, and Confucian scholars all held official positions. A famous example is the Venetian merchant Marco Polo, who served in Kublai's administration for years and described a realm where "the Great Khan shows respect to all religions." The Mongol court even sponsored a major interfaith debate in 1254, which Möngke Khan hosted, and where Buddhist, Christian, and Muslim representatives argued their cases.

The Spread of Buddhism under Mongol Rule

Tibetan Buddhism and the Yuan Dynasty

The most profound impact of the Mongol Empire on religion was the elevation of Tibetan Buddhism to a state-sponsored faith. Kublai Khan invited the Sakya lama Drogön Chögyal Phagpa to his court and appointed him as the Imperial Preceptor. This gave Tibetan Buddhism unprecedented access to imperial patronage. Monasteries in Tibet received land, tax exemptions, and military protection from Mongol forces. The Phagpa script, a new writing system for the Mongolian language, was designed under the lama's direction, tying the Mongol state to Tibetan Buddhist iconography and liturgy.

The Yuan Dynasty also promoted Buddhism more broadly in China. By the 14th century, there were over 40,000 Buddhist monasteries in Yuan territories, many of them funded by the imperial treasury. The Mongol rulers supported the construction of new temples, the translation of Buddhist scriptures into Mongolian and Chinese, and the training of monks. This patronage did not eliminate other religions—Daoism and Confucianism continued to flourish—but it gave Buddhism a privileged position, especially in the capital Dadu (modern Beijing) and in regions like Yunnan and Tibet. The historian Patricia Buckley Ebrey notes that Kublai's favoritism toward Buddhist monks sometimes created tensions with Confucian officials, but the overall effect was to make Buddhism the most visible and protected religion in the empire.

Buddhism Along the Silk Road

The Pax Mongolica—the relative peace imposed by Mongol rule across Eurasia—opened the Silk Road to unprecedented traffic. Merchants, diplomats, and missionaries moved freely between the Mediterranean and the Pacific. This mobility benefited Buddhism, which had long relied on trade routes to spread. Central Asian cities like Samarkand, Bukhara, and Khotan, which had been centers of Buddhist learning before the conquests, experienced a revival. Mongol governors in these regions often funded the restoration of damaged stupas and viharas (monasteries).

Buddhist texts traveled with the caravans. Monks from India and Kashmir journeyed to the Mongol courts, bringing new scriptures and techniques of meditation. The Mongol khans themselves sometimes adopted Buddhist practices: the Ilkhanate in Persia, for example, had several Buddhist temples built in cities like Tabriz and Baghdad, although these later disappeared as the Ilkhanate gradually Islamized. Nevertheless, the Mongol era saw the translation of major Buddhist works into Uyghur, Mongolian, and Chinese, many of which survive today. The influence also reached Korea: the Mongol invasions of Korea in the 13th century led to a period of coexistence, and Korean Buddhist monks traveled to Yuan China to study with Tibetan lamas.

The Expansion of Islam and Christianity

Islam in the Golden Horde and the Ilkhanate

While Buddhism gained from Mongol patronage in the East, Islam expanded significantly in the western parts of the empire. In the Golden Horde (the Mongol khanate in present-day Russia and Ukraine), the khans began converting to Islam in the 13th century. Berke Khan, a grandson of Genghis Khan, became a Muslim in 1257 and encouraged Islamic practices among his subjects. This process accelerated under Öz Beg Khan (r. 1313–1341), who declared Islam the state religion of the Golden Horde. Mosques were built, Islamic law was introduced alongside Mongol yassa, and Sufi orders gained influence. The region's trade with the Middle East intensified, spreading Islamic ideas into the steppes.

In the Ilkhanate (Mongol Persia), the first few rulers were Buddhist and Christian sympathizers, but that changed under Ghazan Khan (r. 1295–1304). Ghazan converted to Islam and launched a campaign to convert the Ilkhanate's Mongol elite. Although some Buddhist temples were destroyed, Ghazan's conversion was followed by a flowering of Islamic culture. He commissioned the Rashid al-Din Hamadani, a Jewish convert to Islam, to write the Jami' al-tawarikh (“Compendium of Chronicles”), a world history that included detailed accounts of the Mongols, China, India, and Europe. This intellectual project demonstrated how Mongol rule could foster Islamic scholarship. The Ilkhanate also maintained contact with Buddhist Tibet—some Mongol generals in Persia remained Buddhists—but by the mid-14th century, the region was overwhelmingly Muslim.

Christian Communities and the Mongol Missions

Christianity also experienced a surge under the Mongols. Nestorian Christians had been present in Central Asia for centuries, and the Mongols, who had no strong attachment to any single religion, often promoted them to key administrative roles. For example, the Mongol commander Kitbuqa, who was a Nestorian Christian, led the invasion of Syria in 1260. The Mongol rulers of the Ilkhanate and the Yuan Dynasty frequently employed Christian officials, and several khans' wives were Nestorian.

The Mongol Empire also attracted European Christian missionaries, who saw an opportunity to convert the Mongols and create an ally against the Islamic powers. The Franciscan friar William of Rubruck traveled to Karakorum in 1253–1255. He attended a public religious debate arranged by Möngke Khan and left a detailed account of the Mongol court's religious diversity. Later, the Franciscan missionary John of Montecorvino was sent by Pope Nicholas IV in 1289 and reached Khanbaliq (Beijing) in 1294. He established the first Roman Catholic mission in China, baptized thousands, and translated the New Testament into Mongolian. His work was supported by the Yuan emperor, who tolerated Christian worship as long as it did not disrupt the peace. Under the Pax Mongolica, Christian communities grew in China, Persia, and the Caucasus. However, after the fall of the Yuan Dynasty and the rise of the Ming, these communities dwindled.

Long-Term Effects on Religious Tolerance and Exchange

The Mongol Empire's policy of religious tolerance was remarkable for its time. While it was not absolute—tax exemptions and political favoritism existed—it did provide a framework in which multiple faiths could coexist without large-scale persecution. This legacy influenced later empires, such as the Timurids and the Mughals, who also practiced a degree of religious pluralism. The Mughal Emperor Akbar, for example, sponsored interfaith debates and established a new syncretic religion called Din-i Ilahi, partly inspired by Mongol precedents.

Religious syncretism also occurred. In Mongolia itself, Tibetan Buddhism gradually supplanted shamanism, but many shamanic practices persisted, creating a unique blend. In the Ilkhanate, the fusion of Mongol and Islamic traditions led to innovations in art and architecture, such as the incorporation of Chinese motifs into Persian miniature painting. The Mongol era also saw the translation of religious texts across languages, facilitated by the diverse scholars at the imperial courts.

However, tolerance had limits. Political loyalty was always the primary criterion. When religious communities rebelled—like the Ismaili Assassins, whom the Mongols destroyed in 1256—or when a religion seemed to threaten Mongol unity, repression could be swift. Yet overall, the Mongol Empire created a network of communication that allowed religious ideas to bypass older political boundaries. The historian Jack Weatherford argues that the Mongols "inadvertently laid the foundation for a global consciousness" by connecting East and West through trade and travel.

Conclusion: The Enduring Legacy

The conquests of Genghis Khan and his successors did not just redraw maps; they reshaped the spiritual world. By establishing a vast, stable, and relatively tolerant empire, the Mongols enabled Buddhism to gain a foothold in Mongolia and China that persists to this day. Tibetan Buddhism, in particular, owes its strong presence in northern China and the Mongol world to the patronage of Kublai Khan and his heirs. Meanwhile, the spread of Islam into Central Asia, Russia, and Persia was accelerated by the conversion of the Ilkhanate and the Golden Horde. Christianity, though ultimately less enduring in the East, left a historical record and a network of missions that linked Europe with Asia.

The long-term effect was a global religious landscape that became more interconnected. The Silk Road exchange of the Mongol period planted seeds not just of faith, but of coexistence. Later empires in India, Iran, and China inherited this tradition of pluralism to varying degrees. Even the religious conflicts of the modern era can be traced back to the balances—and imbalances—that the Mongols created. Today, the legacy of Genghis Khan's policies is visible in the living traditions of Mongolian Buddhism, the Islamic cultures of Central Asia, and the historical memory of a time when the world was more open to the flow of ideas.

For readers interested in deeper exploration, The Metropolitan Museum of Art’s essay on the Yuan Dynasty provides an excellent overview of religious patronage under Kublai Khan. BBC Religions’ timeline of Buddhism contains a useful section on the Mongol period. Additionally, World History Encyclopedia’s article on the Mongol Empire discusses the spread of religions in detail. Finally, a peer-reviewed article in the Journal of Religious History examines the economic vectors of religious exchange under Mongol rule.