Short answers, pulled from the story.
Approximately 90 percent of Myanmar's population practices Buddhism. Burmese census data dating back to 1891 consistently show that between 84 and 90 percent of the population has practiced Buddhism.
Theravada Buddhism is the dominant branch practiced in Myanmar, specifically the Mahavihara Theravada tradition associated with Sri Lankan lineages. Theravada has been the state religion since 1961, though folk practice also incorporates nat spirit worship, esoteric weikza traditions, and historical elements of Mahayana and Brahmanical influence.
Pali historical chronicles record that the Indian emperor Ashoka sent two bhikkhus, Sona and Uttara, to Southeast Asia around 228 BCE. By the 4th century CE, most of the Pyu territory had become predominantly Buddhist, and the oldest surviving Pali Buddhist texts in the world come from the Pyu city-state of Sri Ksetra, dated to the mid-5th to mid-6th century CE.
Ledi Sayadaw, who lived from 1846 to 1923, was a Burmese monk who popularized vipassana meditation as a practice accessible to ordinary laypeople during the British colonial period. He traveled widely, founded lay study and meditation groups, and wrote texts including the Paramattha Sankhip, a Burmese verse translation of a key Abhidhamma work. His teachings directly influenced later figures such as U Ba Khin, S. N. Goenka, and Mahasi Sayadaw, through whom Burmese meditation methods spread internationally.
The Sixth Buddhist Synod was convened by Prime Minister U Nu in 1954 at the Kaba Aye Pagoda in Rangoon, attended by 2,500 monks. Its main output was a new edition of the Pali Canon, called the Sixth Council Tipitaka. The synod also established the International Institute for Advanced Buddhist Studies on the same premises.
Thousands of Buddhist monks joined the pro-democracy protests of 2007 in Myanmar. When the military cracked down, monasteries were raided and monks were imprisoned, tortured, and killed. U Gambira, leader of the All Burma Monks' Alliance, was sentenced in November 2008 to 68 years in prison, later reduced to 63 years, before being released in a mass pardon on the 13th of January 2012.