Kilij Arslan lived two years longer, finally under the protection of his youngest son, Kaikhosrau, who held the capital after him (till 1199) until his elder brother, Rukneddin Suleiman, after having vanquished his other brothers, ascended the throne and obliged Kaikhosrau to seek refuge at the Greek emperor's court.
His son, Kilij Arslan III., was soon deposed by Kaikhosrau (who returned), assisted by the Greek Maurozomes, whose daughter he had married in exile.
Kaikhosrau, therefore, took in 1207 from the Italian Aldobrandini the important harbour of Attalia (Adalia); but his conquests in this direction were put an end to by his attack upon Lascaris, for in the battle that ensued he perished in single combat with his royal antagonist (1211).
The latter conquests were, however, soon lost, and Kaikobad himself died in 12 3 4 of poison administered to him by his son and successor, Ghiyass ed-din Kaikhosrau II.
But, as they crossed the border, Kaikhosrau marched against them, and suffered a formidable defeat at Kuzadag (between Erzingan and Sivas), in 1243, which forced him to purchase peace by the promise of a heavy tribute.
The Mongols retired for some years; but, Kaikhosrau II.
The minister raised his infant son, Ghiyass ed-din Kaikhosrau III., to the throne, and governed the country for ten years longer, till he was entangled in a conspiracy of several amirs, who proposed to expel the Mongols with the aid of the Mameluke sultan of Egypt, Bibars (Beibars or Beybars).
Masud, the son of Izz ed-din, who on the death of his father had fled from the Crimea to the Mongol khan and had received from him the government of Sivas, Erzingan and Erzerum during the lifetime of Kaikhosrau III., ascended the Seljuk throne on the death of Kaikhosrau.
But the most characteristic passage of the epopee is the mysterious disappearance of Shah Kaikhosrau, who suddenly, when at the height of earthly fame and splendour, renounces the world in utter disgust, and, carried away by his fervent longing for an abode of everlasting tranquillity, vanishes for ever from the midst of his companions.