The province of Khurasan (Pers. land of the sun/east) has always been one of the most important regions of the eastern Islamic world. It is often mentioned in medieval Arabic and Hebrew sources. Occupying a strategic location between the Middle East and the rest of Asia, its boundaries were never fixed and changed considerably over time. Today Khurasan is the northeastern province of Iran, but in medieval Islamic geography it extended through the eastern part of the Islamic Empire and included the great desert, Dasht-i Kabīr, as well as parts of what are now Central Asia and Afghanistan.

The…