The Bengal was gradually absorbed into the Delhi Sultanate during the 1200s. It began with Bakhtiar Khilji’s conquest of Gauda between 1202 and 1204 during the reign of Muhammad of Ghor.
The Bengal Sultanate arose after the reign of Muhammad Bin Tughlaq of the Tughlaq Dynasty. In mid-14th century the governors of Bengal announced their independence. The Bengal Sultanate was then formed in 1352 by Shamsuddin Ilyas Shah when he conquered Lakhnauti, Sonargaon and Satgaon.
Shams al-Din Ilyas Shah was the Ilyas Shahi Dynasty's founder. In the conflict between the Delhi Sultanate and the Bengal Sultanate, Firoz Shah Tughluq overcame Ilyas Shah in 1353. Although Firoz slew up to 180,000 Bengalis and even temporarily dislodged Shams al-Din Ilyas Shah from his capital at Pandua, he failed to reannex the delta.
Bengal agreed to pay a tribute to the Delhi Sultan. Despite losing control of many conquered areas, Ilyas Shah remained in firm control of Bengal
Sultan Shams al-Din Ilyas Shah defeated the rulers of Orissa and extended his realm up to Chilika Lake. He raided Jajpur and Cuttack. Ilyas Shah returned to Bengal with plunders from Orissa, including 44 elephants. Ilyas Shah founded the Ilyas Shahi dynasty which ruled Bengal for fifteen decades.
The rise of Bengal Sultanate
