Bengal was an important regional kingdom under the Palas in the eighth century and the Senas in the twelfth century. Bengal was the easternmost province of the Delhi Sultanate.
The long distance, uncomfortable climate and poor means of transport and communications made it difficult for the Delhi Sultanate to control this province. Therefore, it was easy for Bengal to assert its independence. Ghiyasuddin Tughlaq tried to solve the problem by partitioning Bengal into three independent administrative divisions: Lakhnauti, Satgaon and Sonargaon. However, the problems remained and finally Bengal emerged as an independent regional state in the fourteenth century.
In 1342, one of the nobles, Haji Ilyas Khan united Bengal and became its ruler under the title of Shamsh-ud-din Iliyas Shah and laid the foundation of the Ilyas Shah dynasty. He tried to annex Bengal and raided Orissa and Tirhut and forced them to pay tribute. Such expansions alarmed the rulers of the Delhi Sultanate, who tried to occupy Bengal several times but were not successful.
One of the important rulers of the Ilyas Shah dynasty was Ghiyasuddin Azam. He was a learned man and promoted Persian literature. He was well known for dispensing free and fair justice to people. It is said that once he killed a son of a widow by accident. The widow filed a complaint with Qazi who summoned the ruler to the court. When the case was decided, Azam told the Qazi that had he not discharged his duties honestly he would have killed him.
Azam had cordial relations with China. There was a prosperous trading relationship between Bengal and China. The port of Chittagaong was an important centre for exchange of goods. On demand from the king of China, Azam also sent Buddhist monks from Bengal. Pandua and Gaur were the capitals of Bengal.
In 1538, Bengal was annexed by Sher Shah Suri. In 1586, Akbar conquered Bengal, and made it into a suba. While Persian was the language of administration, Bengali developed as a regional language. The establishment of Mughal control over Bengal coincided with the rise of agrarian settlements in the forested and marshy areas of south-eastern Bengal.
Soon after, with the spread of rice cultivation, this area became heavily populated with the local communities of fisher folks and peasants. The Mughals established their capital in the heart of the eastern delta at Dhaka. Officials and functionaries received land grants and settled there.
Alauddin Hussain Shah (1439 to 1519) was another important ruler of Bengal. He was very efficient, and gave high administrative posts to the Hindus and is said to have paid respect to Chaitanya of the Vaisnava sect. He came into conflict with Sikandar Lodhi and had to make peace with him.