Throughout its history, Burma has alternated between periods of unity and disunity. Burma began as a collection of petty kingdoms. It was first unified by a kingdom centered in the city of Pagan on the upper Irrawaddy River. By the end of the 10th century Pagan had conquered much of Upper Burma, and in 1057, under King Anawrahta, it conquered Lower Burma. Anawrahta converted to Hinayana Buddhism and helped to spread the religion throughout Burma. He was the founder of the Pagan Dynasty, which ruled Burma until the Mongol ruler Kublai Khan conquered the country in 1278.
Burma threw off Mongol rule in 1303, but until the 16th century it consisted of a number of separate kingdoms. A local monarch, Tabinshwehti, created a powerful kingdom at Toungoo on the Sittang River in the 1530's and by 1546 had conquered all of Burma, becoming its king. The dynasty he established, the Toungoo Dynasty, lasted until 1752, when civil war caused its collapse. Burma was reunited in 1757 by King Alaungpaya, who established the Konbaung Dynasty.
During the 19th century, as a result of three wars with the British, Burma became a British possession. In the first Anglo-Burmese War (1823–26), Burma surrendered Assam and other regions on the India border. In the second Anglo-Burmese War (1852–53), Lower Burma was annexed to India. After the third Anglo-Burmese War (1885), the remainder of Burma was annexed, in 1886, marking the end of the Konbaung Dynasty. In 1937 Burma became a British crown colony.
The Burma Road, a highway that was the chief supply route to China, made Burma strategically important in World War II. Shortly after Pearl Harbor the Japanese invaded Burma. By May, 1942, they occupied most of the country and cut the Burma Road. After the Japanese set up a puppet government, many Burmese formed an underground movement to aid the Allies. Allied forces freed Burma early in 1945. The British reassumed control, but the Burmese, led by General Aung San, demanded independence. San was assassinated in 1947. Independence was granted in January, 1948, and U Nu became prime minister.
The young nation had to contend with insurgencies by Communists and various ethnic groups, chiefly the Karens. In 1962, a military group led by General Ne Win (later known as U Ne Win) overthrew U Nu's government and set up a one-party socialist regime. The government took over the principal businesses and industries, and throughout the 1960's the Burmese economy stagnated. In 1974 a new constitution was adopted, providing a legal basis for the socialist one-party state established earlier.
In the 1980's U Ne Win relaxed government controls over the economy, but the economy continued to decline. In 1987 U Ne Win resigned; he was replaced by a group of moderate military leaders who promised a return to democracy. Political parties began organizing for elections, but within weeks an ultraconservative military group seized power, abolished the constitution, and imposed a harsh dictatorship. Thousands of supporters of democracy were jailed.
Insurgencies, chiefly by the Shans and Kachins, continued to be a problem. In 1989 the government changed the country's name to Myanmar, a name more acceptable to non-Burmese ethnic groups.
In the 1990 parliamentary election, the National League for Democracy, an opposition party led by Aung San Suu Kyi, won 80 per cent of the seats. The junta annulled the election and arrested nearly all its political opponents, including Suu Kyi.Burma's Independence Day. The British governor, left , and Burma's first president, Sao Shwe Thaik, stand at attention as the new nation's flag is raised on January 4, 1948.
By 2001, hundreds of thousands of Burmese had fled to Thailand, China, and Indonesia. Aung San Suu Kyi was confined to house arrest from September, 2000, to May, 2002, and again in May, 2003, after a violent clash between her supporters and pro-government militants. In November, 2005, the Myanmar government began moving government offices to a new capital named Naypyidaw Myodaw in the center of the country.