An-Nasir Dawud (1206–1261) was a Kurdish ruler, briefly (1227–1229) Ayyubid sultan of Damascus and later (1229–1248) Emir of Kerak.
An-Nasir Dawud was the son of Al-Mu'azzam, the Ayyubid Sultan of Damascus from 1218 to 1227. On his father's death, An-Nasir succeeded, but soon faced opposition from his uncle, Al-Kamil of Egypt, who made war on him, conquering Jerusalem and Nablus. An-Nasir appealed for help to his other uncle, Al-Ashraf, ruler of Harran. Al-Ashraf, however, betrayed his nephew, coming to an agreement with Al-Kamil to divide An-Nasir's lands between them - Al-Ashraf would take Damascus and the north, while Al-Kamil took control of Palestine.
An-Nasir, however, realizing the deception in time, retreated to his capital of Damascus, where he was besieged by the combined armies of his uncle late in 1228. The siege until June 1229, when Al-Ashraf finally captured Damascus, and became ruler, although acknowledging the overlordship of his older brother. An-Nasir was compensated with the lordship of Kerak in the Transjordan region.
An-Nasir Dawud was to rule from Kerak for the next thirty years. In 1239 he returned briefly to prominence when his cousin As-Salih Ayyub, eldest son of Al-Kamil, just expelled from Damascus by rebellion, fell into his hands. An-Nasir held him prisoner, refusing to give him up to Al-Adil II, Ayyub's brother and the ruler of Egypt.
In November 1239, Peter of Brittany (a leader of the Barons' Crusade) attacked a caravan moving up the Jordan to Damascus. An-Nasir was incensed, and marched on Jerusalem, which was almost undefended. He occupied the city, and the garrison of the citadel surrendered on 7 December. An-Nasir did not attempt to hold Jerusalem, however, but merely destroyed the fortifications and withdrew to Kerak.
In April 1240, An-Nasir, quarreling with Al-Adil, released Ayyub and allied with him against the Egyptians, in return for a promise that Ayyub would reinstall him in Damascus. Al-Adil was assassinated by his own troops, and Ayyub and An-Nasir entered Cairo in triumph in June. When An-Nasir returned to Kerak the next month, however, he found himself under attack from the crusaders, who had entered into alliance with his enemy, as-Salih Ismail of Damascus. Meanwhile, Ayyub renounced his promises to restore An-Nasir in Damascus, leaving An-Nasir diplomatically isolated. In order to hold on to his lands, An-Nasir was forced to come to an agreement with Ismail, and then with the Crusaders.