Sogdia

Sogdia, also called Sogdiana, was an ancient Iranian civilisation between the Amu Darya and the Syr Darya rivers, in an area now shared by Uzbekistan, Turkmenistan, Tajikistan, Kazakhstan and Kyrgyzstan. It was a province of the Achaemenid Empire, was conquered by Alexander the Great in 328 BC, and afterwards passed through the hands of the Seleucids, the Greco-Bactrian kingdom, the Kushans, the Sasanians, the Hephthalites and the Turkic khaganates before the Muslim conquest of Transoxiana. Its city-states were never politically united and centred on Samarkand. The Sogdians spoke an eastern Iranian language that served as a lingua franca of Central Asia, and their merchants acted as middlemen along the Silk Road, reaching Tang China and the Byzantine world. Islam gradually replaced their earlier faiths, and Sogdian gave way to New Persian.