Alā ad-Dīn Kayqubād ibn Kaykhusraw (; , 1190–1237), also known as Kayqubad I, was the Seljuq Sultan of Rûm who reigned from 1220 to 1237. He expanded the borders of the sultanate at the expense of his neighbors, particularly the Mengujek Beylik and the Ayyubids, and established a Seljuq presence on the Mediterranean with his acquisition of the port of Kalon Oros , later renamed Ala'iyya in his honor. The sultan, sometimes styled Kayqubad the Great, is remembered today for his rich architectural legacy and the brilliant court culture that flourished under his reign. Kayqubad's reign represented the apogee of Seljuq power and influence in Anatolia, and Kayqubad himself was considered the most illustrious prince of the dynasty. In the period following the mid-13th century Mongol invasion, inhabitants of Anatolia frequently looked back on his reign as a golden age, while the new rulers of the Anatolian beyliks sought to justify their own authority through pedigrees traced to him. Biography Kayqubad was the second son of Sultan Kaykhusraw I, who bestowed upon him at an early age the title malik and the governorship of the important central Anatolian town of Tokat. When the sultan died following the battle of Alaşehir in 1211, both Kayqubad and his elder brother Kaykaus struggled for the throne. Kayqubad initially garnered some allies among the neighbors of the sultanate: Leo I, the king of Cilician Armenia and Tughrilshah, the brothers' uncle and the independent ruler of Erzurum. Most of the emirs, as the powerful landed aristocracy of the sultanate, supported Kaykaus. Kayqubad was forced to flee to the fortress at Ankara, where he sought aid from the Turkman tribes of Kastamonu. He was soon apprehended and imprisoned by his brother in a fortress in western Anatolia. Upon Kaykaus' unexpected death in 1219 (or 1220), Kayqubad, released from captivity, succeeded to the throne of the sultanate. In the Cilicia Campaign in 1225, Cilicia subjugated the Armenian Kingdom. In 1221/1222 Kayqubad launched a naval attack on Sudak which defeated the combined forces of Rus and Cumans. He attack the Armenian Kingdom of Cilicia in 1221 taking the city of Alanya from its governor, Kir Fard. In 1227/1228, Kayqubad advanced into Anatolia, where the arrival of Jalal ad-Din Mingburnu, who was fleeing the destruction of his Khwarezmian Empire by the Mongols, had created an unstable political situation. The sultan settled Turcomans along the Taurus Mountains frontier, in a