Sylhet or Shilhat, as it was known in ancient times, was an expanded commercial center from the ancient period, which explains its original namesake. During this time, Sylhet was Indo-Aryan Brahmins, though ethnically the population would also have traces of Assamese. It has also been suggested that Ancient Kingdom of Harikela was situated in modern Sylhet. Sylhet was certainly known by the rest of India, and is even referred to in the ancient Hindu sacred Tantric text, the Shakti Sangama Tantra, as 'Silhatta'. The last chieftain to reign in Sylhet was Govinda of Gaur, also known as Gaur Govinda.
The 14th century marked the beginning of Islamic influence in Sylhet. A messianic Muslim saint, Hazrat Shah Jalal, arrived in Sylhet in 1303 from Mecca via Delhi and Dhaka with the instructions for aiding Sikhander Khan Ghazi in defeating Govinda of Gaur.Saints such as Shah Jalal or even, Shah Paran were responsible for the conversion of most of the populace from native religion of Hinduism or Buddhism to Islam. Shortly thereafter, Sylhet became a centre of Islam in Bengal. In the official documents and historical papers, Sylhet was often referred to as Jalalbad during the era of the Muslim rule.After the British administrative reorganization of India, Sylhet was eventually incorporated into Assam. It remained a part of Assam for the rest of the era of British rule.