Nasir ad-Din Mahmud I was the sultan of the Seljuk Empire from 1092 to 1094. He succeeded Malik Shah I as Sultan, but he did not gain control of the empire built by Malik Shah and Alp Arslan.
Turkan Khatun, the last wife of Malik Shah, tried to win the throne for her 4 years old son Mahmud, who was proclaimed sultan in Bagdad.
The older son of Malik shah, Barkyaruk was proclaimed too, and the armies of the two pretenders meet in Barudjird, near Hamadan. The forces of Barkyaruk won and took the capital Esfahan. After this, Mahmud and his mother were assassinated by the family of the vizir Nizam al-Mulk. Following Malik Shah I's death, successor states split from the Great Seljuq. In Anatolia Malik Shah I was succeeded by Kilij Arslan I,who escaped from Isfahan; and in Syria by Mahmud's uncle Tutush I. Other governators in Aleppo and Diyabakir declared independence too. The disunity within the Seljuq realms allowed for the unexpected success of the First Crusade shortly afterwards, beginning in 1096. Although his reign was short, Nasir ad-Din Mahmud I ruled with an iron fist.
