Among the many peoples of the world who adopted Islam, several have had a strong Buddhist background, namely the Turks, Afghans, Pakistanis, Indonesians and Malays. Let us look more closely at the spread of Buddhism among the first of these.
The Turki Shahis
The earliest Turkic people to adopt Buddhism were the Turki Shahis. They ruled northwestern India from the mid-3rd to the early 4th centuries CE and then shifted westward to rule modern-day central Afghanistan and eventually central and northern Pakistan until the mid-9th century. They inherited the blend of Hinayana and Mahayana Buddhism of their predecessors in these regions, the Kushans and the White Huns, and were strong patrons of the great monastic centers of study that had previously been founded there. During the late 8th and early 9th centuries, the Turki Shahis were vassal allies of the Tibetan Empire and influenced the flourishing of Buddhism there.
The Eastern and Western Turks
The next major Turkic group to adopt Buddhism were the Gokturks (Göktürk), who gave their name to the Turkic people. The Eastern Turk Empire ruled Mongolia from the end of the sixth to the mid-8th century. Under its royal patronage, Indian, Central Asian and Chinese masters translated many Buddhist scriptures into the Gokturk language. Several of the Gokturk technical Buddhist terms became standard in Central Asia and were later borrowed by the Uighurs and Mongols. The Gokturks blended into their form of Buddhism veneration of the traditional ancient Turkic gods or "tengri," as well as Zoroastrian gods with whom they were familiar from other Central Asian peoples. This eclectic feature was inherited and continued by the Uighurs and Mongols. In the early 8th century, a princess from the Eastern Turk royal family married the emperor of Tibet and was responsible for the invitation to Tibet of many Buddhist monks from Khotan in southern East Turkistan.
The Western Turk Empire was also a great patron of Buddhism from the early 7th to the early 8th century. Its rulers built new monasteries in Uzbekistan. One branch of the Western Turks, the Turgish tribes, was responsible for the spread of Buddhism to Kyrgyzstan and southeastern Kazakhstan during the later part of the 7th and early 8th centuries. The Turgish were also allies of the Tibetan Empire.
The Turgish were replaced in Kyrgyzstan and Kazakhstan in the early 8th century by the Qarluq, an Eastern Turk tribe that also embraced Buddhism and also became an ally of the Tibetans. One branch of the Qarluqs, the Qarakhanids, established a kingdom in eastern Kyrgyzstan and the Kashgar region of southwestern East Turkistan in the mid-9th century. For more than a century, the Qarakhanids followed a blend of Kashgari Buddhism and their native shamanism.
The most prominent Turkic form of Buddhism, however, was with the Uighur people of East Turkistan (Xinjiang). After migrating from Mongolia to the Turfan region of present-day northeastern Xinjiang in the 9th century, they adopted a form of Buddhism that was a blend of elements from the faiths of the Sogdian merchant community from present-day Uzbekistan, the native Tocharians of Turfan and the Chinese merchants of the region. It spread throughout the Uighur Qocho kingdom that spanned all of modern-day Xinjiang except the Kashgar and Khotan regions in the southwest.
The Uighurs, in turn, passed on their form of Buddhism, as well as their alphabet and administrative skills, to the Mongols in the early 13th century at the time of Chinggis Khan. In the later part of the 13th century, the Uighurs shifted the of their practice and adopted the Tibetan form of Buddhism as did their Mongol allies. The Uighurs translated a vast number of Buddhist texts into their Turkic language from Sanskrit, Sogdian, Tocharian, Chinese and Tibetan sources, and were the pioneer translators of the Buddhist scriptures into Mongolian. Their translation style of retaining many Sanskrit technical terms was adopted by the Mongols. Buddhism continued among the Uighurs until approximately the 17th century.
Three other branches of the Uighurs have also been followers of Buddhism. One branch migrated from Mongolia in the mid-9th century to the Chu River valley of northwestern Kyrgyzstan and followed the form of Buddhism practiced there under the patronage of the Qarluq and previously the Turgish Turks. Another group migrated at that time to the Kashgar region of East Turkistan and followed the Kashgari tradition of Buddhism that was also adopted by the Qarakhanid Turks who began to rule the area a century later. The third group are the Yellow Yugurs, who migrated also from Mongolia in the mid-9th century to central present-day Gansu province of China, which was ruled at that time by the Tibetan Empire. Although small in number, the Yellow Yugurs still follow the Tibetan form of Buddhism today.
The last Turkic group to adopt Buddhism were the people of Tuva, in present-day Siberia, just north of western Mongolia. They have been following the Tibetan form of Buddhism in close alliance with the Mongolian subdivision since the 18th century.