foundations for the powerful, but short-lived, Kushan Empire. In the 3rd century AD, Tukhara was under the rule of the Kushanshas (Indo-Sasanians). Tokharistan The form Tokharistan – the suffix -stan means "place of" in Persian – appeared for the first time in the 4th century, in Buddhist texts, such as the Vibhasa-sastra. Tokhara was known in Chinese sources as Tuhuluo (吐呼羅) which is first mentioned during the Northern Wei era. In the Tang dynasty, the name is transcribed as Tuhuoluo (土豁羅). Other Chinese names are Doushaluo 兜沙羅, Douquluo 兜佉羅 or Duhuoluo 覩貨羅. During the 5th century AD, Bactria was controlled by the Xionites and the Hephthalites, but was subsequently reconquered by the Sassanid Empire. 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. Bactrian people Several important trade routes from India and China (including the Silk Road) passed through Bactria and, as early as the Bronze Age, this had allowed the accumulation of vast amounts of wealth by the mostly nomadic population. The first proto-urban civilization in the area arose during the 2nd millennium BC. Control of these lucrative trade routes, however, attracted foreign interest, and in the 6th century BC the Bactrians were conquered by the Persians, and in the 4th century BC by Alexander the Great. These conquests marked the end of Bactrian independence. From around 304 BC the area formed part of the Seleucid Empire, and from around 250 BC it was the centre of a Greco-Bactrian kingdom, ruled by the descendants of Greeks who had settled there following the conquest of Alexander the Great. The Greco-Bactrians, also known in Sanskrit as Yavanas, worked in cooperation with the native Bactrian aristocracy. By