Mesud

Rukn al-Dīn Mesud ibn Kilij Arslan or Mesud I (Modern or Masud was the sultan of the Sultanate of Rûm from 1116 until his death in 1156.

Reign Following the defeat and death of his father Kilij Arslan fighting against Ridwan of Aleppo at the Battle of Khabur River in 1107, Mesud was passed over for the throne, in favor of his brother Malik Shah. Following Malik Shah's defeat at the hands of Byzantine Emperor Alexios I Komnenos, at the Battle of Philomelion in 1116, Mesud rebelled. Later in 1116, with the help of his father-in-law, the Danishmend ruler Gümüshtigin , Mesud captured Konya and defeated Malik Shah, blinding and eventually having him murdered. 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.

In 1146, Mesud successfully fended off a Byzantine attack on his capital and toward the end of his reign, fought against the armies of the Second Crusade, one led by Emperor Conrad III of Germany and the other led by King Louis VII of France. Mesud defeated both of them; the first at the battle of Dorylaeum near modern Eskişehir in 1147 and the second army in Laodicea near modern Denizli in 1148. He invaded the Principality of Antioch in September 1149 and captured Marash.

Emperor Manuel I Komnenos persuaded Mesud I to attack Thoros II and demand his submission to the Sultan's suzerainty. However, the ensuing Seljuk attack, which in fact was provoked by an Armenian raid into Seljuk lands in Cappadocia in the winter of 1154, was routed successfully by Thoros in collaboration with a contingent of the Knights Templar.

The Alâeddin Mosque in Konya was built during the reign of Mesud I. The building served as the “Mosque of the Throne” for the Seljuq Sultans of Rum and contains the dynastic mausoleum.

When he died, Mesud was succeeded by his son Kilij Arslan II.

Kamero, one of Mesud's daughters married John Tzelepes Komnenos, a member of the royal house of Komnenos who had converted to Islam.