Khorasan

Khorasan is a historical region of the Iranian Plateau in West and Central Asia whose name, from Persian, means where the sun arrives from or the eastern province; it was first organized as an administrative division under the Sasanian Empire around the sixth century. At its fullest historical extent Khorasan covered western and northern Afghanistan, northeastern Iran, the eastern halves of Turkmenistan and Uzbekistan, western Tajikistan, and parts of Kyrgyzstan and Kazakhstan, and was traditionally divided into four quarters centered on the cities of Nishapur, Merv, Herat, and Balkh. The region remained strategically important through the Umayyad, Abbasid, Seljuq, and Timurid empires, and suffered devastating Mongol invasions in the thirteenth century. Until those invasions Khorasan served as the cultural capital of Persia, producing scholars including Avicenna, al-Farabi, Omar Khayyam, and al-Khwarizmi, and the New Persian literary language developed and spread from the region across the wider Iranian world.