As the Seljuq army approached, Queen Russudan of Georgia sued for peace, offering her daughter Tamar in marriage to Kaykhusraw.
The architect of his early reign was a certain Sa'd al-Din Köpek, master of the hunt and minister of works under Kayqubad.
Köpek excelled at political murder and sought to protect his newfound influence at the court with a series of executions.
While the Mongols threatened the Seljuq state from the outside, a new danger appeared from within: a charismatic preacher, Baba Ishak, was fomenting rebellion among the Turkmen of Anatolia.
Both their number and the persuasive power of their religious leaders, nominally Islamized shamans known as babas or dedes,[10] played a large part in the conversion of formerly Christian Anatolia.
The Persianized Seljuq military class expended considerable effort keeping these nomads from invading areas inhabited by farmers and from harassing neighboring Christian states.
Unlike his predecessors, whose influence was limited to smaller tribal groups, Baba Ishak's authority extended over a vast population of Anatolian Turkmen.
Simon of Saint-Quentin, an envoy of Pope Innocent IV on his way to the Great Khan, offers an account of the sultan's preparations.
[12] In addition to these, Kaykhusraw commanded the Seljuq army and irregular Turkmen cavalry, though both had been weakened by the Baba Ishak rebellion.
[13][14] Kaykhusraw built a large army to confront the invasion, but his 80,000-strong force lacked the discipline and cohesion of the Mongols.
The Mongols failed to capture either the sultan's treasury or his capital when they had the chance, and his Anatolian lands escaped the worst of the invaders’ depredations.
Between 1240 and 1243 (638 and 641 A.H.) a series of remarkable silver dirhams were struck in Kaykhusraw's name at Sivas and Konya depicting a lion and sun.
One suggests that the images represent the constellation Leo, the astrological sign of Kaykhusraw's beloved Georgian wife Tamar.