Kaykaus ibn Kaykhusraw or Kayka'us II (, , ÿIzz ad-Dën KaykÃÂwus ibn Kaykhusraw) was the sultan of the Seljuqs of Rûm from 1246 until 1262.
Kaykaus was the eldest of three sons of Kaykhusraw II. His mother was Prodoulia, who was a Byzantine Greek, may have had Kaykaus baptized as a child. It was common for the Christian slave-concubines and wives of the Seljuk harem to baptise their sons. He was a youth at the time of his father's death in 1246 and could do little to prevent the Mongol conquest of Anatolia. For most of his tenure as the Seljuk Sultan of Rûm, he shared the throne with one or both of his brothers, Kilij Arslan IV and Kayqubad II. Mongol commander Baiju threatened him and warned him of being late with paying tribute and requested new pastures in Anatolia for the Mongol cavalry. The Mongols defeated Kaykaus who then fled to the Empire of Nicaea in 1257 with his children and followers.
He exchanged messages with the Nicaean Emperor Theodore II Laskaris before his arrival and was welcomed in Sardis and given gifts. The Emperor helped Kaykaus regain his lands by giving him a modest force of 400 soldiers under primmikerios Isaac Doukas Mourtzouphlos. In exchange for the aid, Kaykaus returned to the Byzantines Laodicea, Chonae and the two small fortresses of Sakaina and Ypsele. With the forces he was given, he managed to recapture Iconium.
Kaykaus ruled for only a few years, as he had to flee again to Byzantium following the civil war with Kilij Arslan IV (who was supported by the Mongols) around the summer of 1262. The Byzantine court welcomed him as before, along with his mother, wife, four sons, daughter, sister and his two maternal uncles Kyr KhÃÂya and Kyr Kattidios. Soon however tensions grew between the former Sultan and the new Emperor Michael VIII Palaiologos in the midst of the Arsenite Schism, and Kaykaus tried to depose him. After the plot was uncovered, Kaykaus fled to Ainos, while his family was sent to Berroia. Kaykaus' brother Kayqubad appealed to Berke Khan and his nephew Nogai of the Golden Horde. Bulgarians and Tatars jointly invaded Thrace in the winter of 1264/1265 and Kaykaus fled with them. Berke gave Kaykaus an appanage in Crimea and had him married to his daughter, Urbay Khatun. He died an exile in 1279 or 1280 in Crimea.
According to Rustam Shukurov, Kaykaus II "had dual Christian and Muslim identity, an identity which was further complicated by dual Turkic/Persian and Greek ethnic identity". Kaykaus and his sons were all said to be baptised, and whilst in Constantinople the family visited church baths, received communion and attended Easter services under the watch of the Patriarch Arsenios. Even when in Crimea, Kaykaus still insisted on his Christian faith, defending Arsenios against charges of noncanonical communication with pagans (Kaykaus and his family) by asking for the engolpion he'd left in Constantinople and offering to eat pork to prove his orthodoxy.
In addition to his Mongol bride Urbay Khatun, daughter of Berke Khan, Kaykaus had multiple wives, though only one accompanied him to Byzantium. The Armenian Kirakos Gandzaketsi reported that Kaykaus was married to a daughter of the emperor John III Doukas Vatatzes, and later Ottoman sources give her name as Anna, however both of these claims are unreliable and likely only indicate that his wife was Christian and possibly Roman (Byzantine). Christian Greek women were the dominant origin of the slave-concubines in the Seljuk harem. This wife continued to live in Constantinople following Kaykaus' escape.
Kakyaus' children, all with unknown mothers were:
Though deposed and exiled, Kaykaus remained popular among the Turkmen of Anatolia and a threat to the stability of the fragile Seljuq-Mongol relationship. The vizier Fakhr al-Din Ali was imprisoned for a time in 1271 for corresponding with him. It was from Kaykaus that KaramanoÃÂlu Mehmed Bey in 1276 sought help in his uprising against the Mongols. Since Kaykaus was in no position to help, Mehmed Bey thought it best to have a representative of Kaykausâ line on his side, even if only an imposter, and named Jimri as head of the revolt. Kaykaus later dispatched several of his sons from the Crimea as pretenders, one of which, Masud II, was ultimately successful in winning the Seljuq throne in 1280.
Some modern historians consider the Byzantine noble Athanasios Soultanos to have been the brother or son of Kaykaus, but this is unlikely due to the later age Soultanos lived in. However another branch of the Christianized aristocratic family of the Soultanoi was indeed begun by a close relative of Kaykaus, whence their name.
In the Ottoman period the rebel Sheikh Bedreddin, who drew support largely from Turkmen migrants to the Balkans, claimed descent from Kaykaus II.