In 1250, when the Ayyubid sultan of
Egypt as-Salih Ayyub died and his son
Turanshah was murdered by the
Bahri Mamluks of Egypt,
Shajar al-Durr (widow of as-Salih Ayyub ) seized the throne of Egypt. An-Nasir Yusuf, being an Ayyubid, refused to recognize Shajar al-Durr as the Sultana of Egypt and, as a sign of support, the
Emirs of
Syria granted him the city of Damascus, in Syria. In January 1251, an-Nasir Yusuf led another army to Egypt and clashed with Aybak's army, whose vanguard was led by
Qutuz, in a significant battle that led to Yusuf's defeat. He fled back to Damascus, though some of his soldiers who could reach Cairo spread the initial impression inside Egypt that Yusuf had won the battle. Later when the news of Aybak's ultimate victory arrived, the soldiers and their commanders were arrested, and Aybak sent back the soldiers, some 3,000 in number, to Damascus on the backs of donkeys. In 1253, through mediation of some Emirs, an accord was reached between an-Nasir Yusuf and Aybak which gave the Egyptians control over
Gaza,
Jerusalem,
Nablus, and the coastline of
al-Sham. In 1254, another power shift occurred in Egypt, as Aybak killed
Faris ad-Din Aktai, the leader of the Bahri Mamluks. Some of his Mamluks, among them
Baibars al-Bunduqdari and
Qalawun al-Alfi, fled to an-Nasir Yusuf in Syria, persuading him to break the accord and invade Egypt. Aybak wrote to an-Nassir Yusuf warning him of the danger of these Mamluks who took refuge in Syria, and agreed to grant him their territorial domains on the coast, but an-Nasir Yusuf refused to expel them and instead returned to them the domains which Aybak had granted. In 1255, an-Nasir Yusuf sent new forces to the Egyptian border, this time with many of Aktai's Mamluks, among them Baibars al-Bunduqdari, and Qalawun al-Alfi, but he was defeated again. ==Relations with Crusaders==