Islam is the largest religion in Bangladesh.
The Muslim population is approximately 145.3 million, which is the fourth largest Muslim population in the world, constituting 89.6% of the total population. Religion has always been a strong part of identity, but this has varied at different times. A survey in late 2003 confirmed that religion is the first choice by a citizen for self-identification; atheism is extremely rare. Bangladesh is a secular state, however the United Nations has recognised the country as mainly moderate Muslim democratic country.
Islam arrived to the region of Bengal since the 13th century, mainly by the arrivals of Arab traders, Persian Saints and conquests of the region. One of the notable Muslim saint was, Shah Jalal. He arrived in the region of Sylhet in 1303 with many other disciples to preach the religion to the people. The majority of Muslims in Bangladesh are Sunni.
The country's largest mosque is Baitul Mukarram, it also the country's national mosque, and the 10th largest mosque in the world.