Arabic): ("The people of the Khwarezm were a branch from Persian tree.") The area of Khwarezm was under Afrighid and then Samanid control until the 10th century before it was conquered by the Ghaznavids. The Iranian Khwarezmian language and culture felt the pressure of Turkic infiltration from northern Khwarezm southwards, leading to the disappearance of the original Iranian character of the province and its complete Turkicisation today, but Khwarezmian speech probably lasted in upper Khwarezm, the region round Hazarasp, till the end of the 8th/14th century. The Khwarezmian language survived for several centuries after Islam until the Turkification of the region, and so must some at least of the culture and lore of ancient Khwarezm, for it is hard to see the commanding figure of Al-Biruni, a repository of so much knowledge, appearing in a cultural vacuum. Achaemenid period The Achaemenid Empire took control of Chorasmia possibly during the reign of Cyrus the Great in the 6th century BC, and certainly by the time of King Darius I (ruled 550–486 BC). The son of Cyrus Smerdis/Bardiya became the governor of the region, along with Bactriana, Carmania, and the other eastern provinces of the empire. And the Persian poet Ferdowsi mentions Persian cities like Afrasiab and Chach in abundance in his epic Shahnama. The contact with the Achaemenid Empire had a great influence on the material culture of Chorasmia, starting a period of rich economic and cultural development. Chorasmian troops participated in the Second Persian invasion of Greece by Xerxes in the 480 BC, under the command of Achaemenid general and later satrap Artabazos I of Phrygia. By the time of the Persian king Darius III, Khwarazm had already become an independent kingdom. Hellenistic period Chorasmia was involved in the conquests of Alexander the Great in Central Asia. When the king of Khwarezm offered friendship to Alexander in 328 BC, Alexander's Greek and Roman biographers imagined the nomad king of a desert waste, but 20th-century Russian archeologists revealed the region as a stable and centralized kingdom, a land of agriculture to the east of the Aral Sea, surrounded by the nomads of Central Asia, protected by its army of mailed horsemen, in the most powerful kingdom northwest of the Amu Darya (the Oxus River of antiquity). The king's emissary offered to lead Alexander's armies against his own enemies, west over the Caspian towards the Black Sea (e.g. Kingdom of Iberia and