Khurasan 600–1500

“Khurasan,” meaning the country of the “rising sun,” had a much wider designation in pre‐ and early Islamic times. From the sixth century, Khurasan seems to have been constituted of an original nucleus, or “Khurasan Proper,” which has been tentatively located within the Marv Oasis, Herat, and Zuzan, following the eastern border of the Iranian Deserts to the southeastern corner of the Caspian Sea, including the province of Gorgan following the line of the Great Wall, which in the light of recent research is dated to the fifth to sixth centuries. Arab troops penetrated as early as 651, but its complete control only occurred after the victory of al‐Maʿmun against his brother ʿAmin in the beginning of the ninth century. The Tahirids were the greatest dynasty controlling the whole of Khurasan, which later under the Samanids became as vast as the whole eastern Islamic Empire. Afterward, Khurasan did not recover its previous politic centrality, although it retained its crucial strategic role, in which its capitals continued to be main cultural and economic centers.