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Introduction of Islam

By the mid-7th century AD, Islam under the Rashidun Caliphate had come to rule much of the Middle East and western areas of Central Asia.

In 663 AD, the Umayyad Caliphate attacked the Buddhist Shahi dynasty ruling in Tokharistan. The Umayyad forces captured the area around Balkh, including the Buddhist monastery at Nava Vihara, causing the Shahis to retreat to the Kabul Valley.

In the 8th century AD, a Persian from Balkh known as Saman Khuda left Zoroastrianism for Islam while living under the Umayyads. His children founded the Samanid Empire (875–999 AD). Persian became the official language and had a higher status than Bactrian, because it was the language of Muslim rulers. It eventually replaced the latter as the common language due to the preferential treatment as well as colonization.