Burma is a large Southeast Asian country between India and Thailand and where about 87% of the people call themselves Buddhists. Theravāda Buddhism existed in the Mon country of southern Burma from perhaps as early as the first millennium, but only became the religion of all Burma after the 11th century. Before that Brahmanism, Mahāyāna and Vajrayāna were the main religions. Today, Burmese monks have a reputation for dedication to meditation and abhidhamma study. In 1989 the military government of Burma changed the country’s name to Myanmar.
Buddhism in Myanmar - A Short History, Roger Bischoff,1995.