Abu Ali Hasan ibn Ali Tusi (April 10, 1018 – October 14, 1092), better known by his honorific title of Nizam al-Mulk (Persian: نظام‌الملک‎‎, "Order of the Realm") was a Persian scholar and vizier of the Seljuq Empire. He held near absolute power for 20 years after the assassination of Alp Arslan in 1072. One of his most important legacies was founding madrasas in cities throughout the Persian Empire. These were called "nezamiyehs" after him.