He was still a commander under Sultan
Qutuz at the
Battle of Ain Jalut in 1260 when he decisively defeated the Mongols. After the battle, Sultan Qutuz (aka Koetoez) was assassinated while on a hunting expedition. It was said that Baibars was involved in the assassination because he expected to be rewarded with the governorship of
Aleppo for his military success; but Qutuz, fearing his ambition, refused to give him the post, disappointing him.
[15] Baibars succeeded Qutuz as Sultan of Egypt.
Once Baibars had ascended to the Sultanate, his authority was soon confirmed without any serious resistance, except from
Sinjar al-Halabi, another Mamluk amir who was popular and powerful enough to claim
Damascus. Also, the threat from the Mongols was still serious enough to be considered as a threat to Baibars' authority. However, Baibars first chose to deal with Sinjar, and marched on Damascus. At the same time the princes of
Hama and
Homs proved able to defeat the Mongols in the
First Battle of Homs, which lifted the Mongol threat for a while. On 17 January 1261, Baibars' forces were able to rout the troops of Sinjar outside Damascus, and pursued the attack to the city, where the citizens were loyal to Sinjar and resisted Baibars, although their resistance was soon crushed.
After suppressing the revolt of Sinjar, Baibars then managed to deal with the
Ayyubids, while quietly eliminating the prince of Kerak. Ayyubids such as
Al-Ashraf Musa, Emir of Homs and the Ayyubid Emir Dynasty of Hama (presumably
Al-Afdal Muhammad), who had earlier staved off the Mongol threat, were permitted to continue their rule in exchange for their recognizing Baibars' authority as Sultan
[17]
The next step which Baibars needed after this was religious authority, so he sought legitimation from the Caliph in
Baghdad, which was sacked by
Ilkhanate Mongol army earlier[
clarification needed]. So by becoming a protegee of the Caliph, he had all he needed
[17]
In 1271, after Baibars captured the smaller castles in the area, including
Chastel Blanc, he besieged Krak des Chevaliers castle, held by the
Hospitallers, on 30 March. Peasants who lived in the area had fled to the castle for safety and were kept in the outer ward. As soon as Baibars arrived he began erecting
mangonels, powerful siege weapons which he would turn on the castle. According to Ibn Shaddad, two days later the first line of defences was captured by the besiegers; he was probably referring to a walled suburb outside the castle's entrance.
[29] After a lull of ten days, the besiegers conveyed a letter to the garrison, supposedly from the Grand Master of the Knights Hospitaller in Tripoli, which granted permission for them to surrender. The garrison capitulated and the Sultan spared their lives.
[29] The new owners of the castle undertook repairs, focused mainly on the outer ward.
[30] The Hospitaller chapel was converted to a
mosque and two
mihrabs were added to the interior.
[31]
Baibars then turned his attention to Tripoli, but he interrupted his siege there to call a truce in May 1271. The fall of Antioch had led to the brief
Ninth Crusade, led by
Prince Edward of England, who arrived in Acre in May 1271 and attempted to ally himself with the Mongols against Baibars. So Baibars declared a truce with Tripoli, as well as with Edward, who was never able to capture any territory from Baibars anyway. According to some reports, Baibars tried to have Edward assassinated with poison, but Edward survived the attempt and returned home in 1272.