Nasir al-Din Mahmud, born in 1216, was the Zengid hereditary Emir of Mosul from 1219 to 1234 (died 18 years old). He was successor to his brother Nur al-Din Arslan Shah II, and was only three years old when he ascended the throne.^[1] He was the last Zengid ruler of Mosul, and remained under the control of the atabeg of Mosul, Badr al-Din Lu'lu'.^[1] Badr al-Din Lu'lu' may have assassinated the young ruler following the death of his maternal grandfather the Emir of Erbil, Muzaffar al-Din Gökböri. Lu'lu' then began to rule Mosul in his own right.^[2]