Rukunuddin Kaikaus (Persian: رکن الدین کیکاوس, Bengali: রুকনউদ্দীন কায়কাউস) was an independent Sultan of Bengal who ruled from 1291 to 1300 CE.
During his reign, he had divided his kingdom into two parts - Bihar and Lakhnauti, and appointed Ikhtiyaruddin Firoz Itgin as the Governor of Bihar and Shahabuddin Zafar Khan Bahram Itgin as the Governor of Lakhnauti.
His kingdom extended to Bihar in the west, Devkot in the north and Satgaon in the south.
Delhi Sultan Alauddin Khalji also accepted Kaikaus's independent dominance of Bengal.
[2] On Muharram 692 AH (1292-1293 CE), Kaikaus ordered Ikhtiyaruddin Firuz Aitigin to construct a mosque north of Maheswar in Bihar, on the banks of the Burhi Gandak River.