ruler of the Seljuk Sultanate of Rüm
1233 CE to 1280 CE
Kaykaus II or Kayka'us II is the eldest of three sons of Kaykhusraw II.
Bayju defeats Kaykaus II, ruler of the Seljuq realm west of the river Kizilirmak, near Aksaray in October 1256, making all Anatolia officially subject to Möngke Khan.