According to the Pew Research Center, , 62.9% of the population of Eritrea adhered to Christianity, 36.6% followed Islam, and 0.4% practiced folk religion. The remainder observed Judaism, Hinduism, Buddhism, other faiths (<0.1% each), or were religiously unaffiliated (0.1%). The U.S. Department of State estimated that, , 50% of the population of Eritrea adhered to Christianity, 48% followed Islam, and 2% observed other religions, including traditional faiths and animism. Christianity is the oldest world religion practiced in the country, and the first Christian monastery Debre Sina (monastery) was built during the 4th century.