Battle of Elbistan

On April 15, 1277, the Mamluk Sultan Baibars marched from Syria into the Mongol-dominated Seljuk Sultanate of Rûm and attacked the Mongol occupation force in the Battle of Elbistan (Abulustayn). Upon reaching Elbistan with at least 10,000 horseman, Baibars made ready for battle with the Mongols, expecting them to be around 30,000. However, although the Mongol forces were smaller than the Mamluk army, there were the Georgians and Rum Seljuks that bolstered their numbers.
The battle.
The Mongols attacked first and charged the Mamluk heavy cavalry. At the start of the battle many of the Bedouin irregulars in the Mamluk army were also killed. Their attack was concentrated on the left flank of the Mamluk army. This resulted in the Sultan's standard bearers (sanjaqiyya) being killed. The Mamluks however were able to regroup and launch a counter-attack. Baibars himself went with a few troops to deal with the Mongol right flank that was pounding his left flank. Baibars ordered a force from the army from Hama to reinforce his left. The large Mamluk numbers were able to overwhelm the Mongol force. The Mongols instead of retreating dismounted from their horses. Some Mongols were able to escape and took up positions on the hills. Once they became surrounded they once again dismounted, and fought to the death. During the battle, the Mongols destroyed the Mamluk left wing, consisting of many Bedouin irregulars, but were ultimately defeated.
It seems that both sides were expecting assistance from the army of the Pervâne and his Seljuks. The Pervâne had attempted to ally himself with both factions to keep his options open, but fled the battle with the Seljuk Sultan to Tokat. The Seljuk army was present near the battle, but did not take part. After the battle many Rumi soldiers were taken captive. Others joined the Mamluks willingly. Pervane's son Muhadhdhab al-Din was captured. In addition many Mongol officers and common soldiers were taken prisoner. Two of the soldiers captured, Qipchaq and Salar, would become mamluks of Qalawun and would become very important amirs. The Mongol officers' lives were spared as well.
Aftermath.
After Baibars victory, he marched unopposed to Kayseri (Qaysariyya) in the heart of Anatolia in triumph and entered it on April 23, 1277; just over a month after the battle. The Muslim festival of Eid al-Adha happened around this time. In this festival, Baibars forbade the beating of drums of good tidings telling his emirs: "How can I rejoice? I had believed that if 10,000 horsemen of my army were to meet 30,000 Mongols, I would defeat them. But I met 7000 Mongols with all my army. The Mongols aroused panic and my army lost heart. The Mongols defeated the Muslim Left. Without Allah's grace, they would have defeated us. If I met them, and they were equal to the Muslims in size, or larger than they, then the matter would not have turned out well". Following the festival, Baibars left Rum and died in Syria soon after.
In light of Baibar's victory Pervâne attempted to draw in the Mamluks into a confrontation with a fresh Mongol army led by Abaqa himself. However, Baibars was running low on supplies, and his equipment repaired. The possibility of a new Mongol army convinced Baibars to return to Syria since he was so far away from his bases and supply line. As the Mamluk army returned to Syria the commander of the Mamluk vanguard, Izz al-Din Aybeg al-Shaykhi deserted to the Mongols. Pervâne sent a letter to Baibars asking him to delay his departure. Baibars chastised him for not aiding him during the Battle of Elbistan. Baibars told him he was leaving for Siwas to mislead Pervâne and the Mongols to his true destination. Baibars also sent Taybars al-Waziri with a force to raid an Armenian town called al-Rummana, whose inhabitants had hidden the Mongols earlier.
The Mongol Ilkhan Abaqa, meanwhile reasserted his authority in Rum. After Abaqa surveyed the battlefield he became very angry. He ordered the Muslim population of Kayseri (Qaysariyya) and eastern Rum to be put to death. Large numbers of people were killed. Abaqa's army had to put down a rebellion of Qaramanid Turkmen who declared their loyalty to Baibars. He sent an army of 30,000 towards Syria, but after learning the size of Baibars army from Aybeg al-Shaykhi he called his forces back. He wanted to send the army in the summer but his officers persuaded him to wait until the winter. However, the expedition was never sent. The Ilkhan Mongols were having logistical problems of their own, and many of the troops were called back to Ilkhanate lands. Abaqa entrusted the country to his other brother Qonghurtai and Shams al-Din Juwayni. At first Abaqa turned a blind eye to Pervâne. The Mongol nobles and noblewomen convinced him to have him put to death. Pervâne's flesh was eaten by Abaqa and the senior Mongols as an act of revenge according to King Het'um of Armenia.
During the celebration of victory, Baybars said that "How can I be happy. I thought that I and my servants would defeat Mongols before, but my left wing was beaten by them. Only Allah helped us".