Neyshābūr was the feudal capital of a Seljuq Türk at the beginning of the 12th century. The principality (and the empire generally) suffered a series of defeats by various groups, with much of Khorāsān falling to the Khwārazm Empire (with a capital far to the north) by century's end. Neyshābūr's population declined during these troubles and changes.