The Bengali Muslim population was a product of conversion and religious evolution, and their pre-Islamic beliefs included elements of Buddhism and Hinduism. The construction of mosques, Islamic academies (madrasas) and Sufi monasteries (khanqahs) facilitated conversion, and Islamic cosmology played a significant role in developing Bengali Muslim society. Scholars have theorised that Bengalis were attracted to Islam by its egalitarian social order, which contrasted with the Hindu caste system. One of the notable Muslim preachers was Shah Jalal who arrived in the region of Sylhet in 1303 with many other disciples to preach the religion to the people. By the 15th century, Muslim poets were writing in the Bengali language. Notable medieval Bengali Muslim poets included Daulat Qazi, Abdul Hakim and Alaol. Syncretic cults, such as the Baul movement, emerged on the fringes of Bengali Muslim society. The Persianate culture was significant in Bengal, where cities like Sonargaon became the easternmost centers of Persian influence.