Arslan-shah came to Hamedan with the Tutor Ildeniz and he was enthroned there. Semseddin Ideniz established dominion in the entire Iraq Seljuks State as the tutor of the sultan. The Caliph Mustencid rejected the proposal of the delivery of prayers in the name of Arslan-shah. On the other hand, some of emirs and particularly Inanc who was the ruler of Rey were unable to stand the power and influence of Ildeniz that he had acquired within the state. These emirs decided to fight against him and they made an alliance. These emirs collaborated with the Prince Muhammed who had been in Shiraz and moved towards Hamedan. The Tutor Ildeniz and the Emir Gurd-bazu collected their forces and they moved against their opponents together with the Sultan Arslan-shah. The two armies fought within the environs of Hamedan. The war ended with the defeat of the Prince Muhammed and his supporters (1161). When Arslan-shah became the sultan of the state, he provided the peace and security in Iraq Seljuks State due to the powerful authority of his Tutor, Semseddin Ildeniz. It was obvious that the Abbasi caliphate that desired to live his old influential days could not tolerate to this powerful state any more. Therefore, the Abbasi Caliph wanted the weakness of the Iraq Seljuks State. But his arrangements to this effect had not yielded the desired effects and Arslan-shah was recognised as the sultan by most of the emirs that dominated in various regions of Iraq.
Arslan-shah was recognised as sultan in the entire Iran, Mosul, el-cezire and the Eastern Anatolia. However, the state administration was in the hands of his stepfather, Ildeniz. Sultan Arslan-shah sometimes complained about this situation. Pursuant to the death of Ildeniz, the sultan Arslan-shah wanted to get rid of the Tutor Pehlivan Muhammed upon the encouragement of the other emirs. The emirs that encouraged the sultan gathered around him together with their forces. Arslan-shah set in motion towards Azerbaijan in order to fight with Pehlivan. However, he got sick in Zencan. Under these circumstances, he preferred to make peace with Pehlivan and he assigned the state administration to him. Sultan Arslan-shah died in Hamedan in the year of 1175.