Sogdians formed ancient Iranian civilization in Central Asia between Amu Darya and Syr Darya rivers. City-states centered on Samarkand never politically united. Sogdian language extinct except Yaghnobi descendant. Sogdians conquered by Cyrus, Alexander, Seleucids, Kushans, Sasanians, Hephthalites, Turks, Arabs. Acted as essential Silk Road middlemen trading silk, luxury goods from China to Byzantium. Converted fully to Islam by 999 AD coinciding with language decline. Named from Indo-European root for archer via etymological shifts. Possessed Bronze Age urban culture from 4th millennium BC. Mentioned as Gava in Avesta as second good land created by Ahura Mazda. Incorporated into Achaemenid Empire with Sogdian soldiers in Xerxes' army. Received Greek population via Achaemenid ethnic cleansing of rebels. Lived nomadically like Yuezhi but settled for agriculture and trade. Resisted Alexander fiercely until Spitamenes killed. Alexander married Sogdian Roxana and promoted intermarriages. Military power never recovered post-Hellenistic period. Ruled by Greco-Bactrians then overrun by Sakas and Yuezhi. Became Sasanian satrapy then Hephthalite territory with prosperity from tributes. Turks allied with Sasanians defeated Hephthalites retaining Sogdia. Became cosmopolitan under Turks with Chinese, Korean delegates. Qutayba initiated Muslim conquest with Sogdian revolts crushed. Mass Sogdian emigration east after conquests. Samanids supplanted Sogdian language with Persian and eradicated old religions. Dominated caravan trade networks across 1500 miles to China. Monopolized India-China trade by 4th century. Protected by Göktürks whose empire relied on Sogdian economic power. Established sabao administrators in China with Zoroastrian temples. Served as Tang soldiers but An Lushan rebellion led to Sogdian massacres. High-nosed Sogdians slaughtered in Youzhou by rebels. Han Chinese bought Sogdian slave girls for sex. Sogdian women abandoned in China cursed husbands as worse than pigs or dogs.