Malik Ikhtiyaruddin Iuzbak became the Governor of Bengal in 1251 CE.
History
After taking power, Iuzbak repulsed the Oriyas from south-western Bengal. After this victory he styled himself as the independent ruler of Bengal. He adopted the title Sultan Mughisuddin Abul Mujaffar Iuzbak.
He invaded Bihar and Oudh. In 1257 he extended his expedition to Kamarupa (present-day Assam). But it was a failed attempt and he was killed in the battle.
References
Malik Ikhtiyaruddin Iuzbak Wikipedia(Text) CC BY-SA