Following the defeat and death of his father Kilij Arslan fighting against Ridwan of Aleppo at the battle of Khabur river in 1107, Mesud lost the throne in favor of his brother Malik Shah. With the help of the Danishmends, Mesud captured Konya and defeated Malik Shah in 1116, later blinding and eventually murdering him. Mesud would later turn on the Danishmends and conquer some of their lands. In 1130, he started construction of the Alâeddin Mosque in Konya, which was later completed in 1221.