By 849, Burmans had founded a powerful kingdom centred on the city of Pagan and filled the void left by the Pyu. The kingdom grew in relative isolation until the reign of Anawrahta (1044 - 77) who successfully unified all of Myanmar by defeating the Mon city of Thaton in 1057. Consolidation was accomplished under his successors Kyanzittha (1084-1112) and Alaungsithu (1112-1167), so that by the mid-12th century, most of Southeast Asia was under the control of either the Bagan Kingdom or the Khmer empire. The Bagan kingdom went into decline as more land and resources fell into the hands of the powerful sangha (monkhood) and the Mongols threatened from the north. The last true ruler of Bagan, Narathihapate (reigned 1254-87) felt confident in his ability to resist the Mongols and advanced into Yunnan in 1277 to make war upon them. He was thoroughly crushed at the Battle of Ngasaunggyan, and Bagan resistance virtually collapsed. The king was assassinated by his own son, but the dynasty was soon brought to an end in 1289, when the Mongols installed a puppet ruler in Myanmar.

Bagan (formerly Pagan, formally titled Arimaddanapura (the City of the Enemy Crusher) and also known as Tambadipa (the Land of Copper) or Tassadessa (the Parched Land), was the ancient capital of several ancient kingdoms in Myanmar. It is located in the dry central plains of the country, on the eastern bank of the Ayeyarwady River, 145 kilometres (90 miles) southwest of Mandalay.

The religious buildings of Bagan are often reminiscent of popular architectural styles in the period of their constructions. The most common types are:

• Stupa with a relic-shaped dome
• Stupa with tomb-shaped dome
• Sinhalese-styled stupa
• North Indian model
• Central Indian model
• South Indian model
• Mon model

The ruins of Bagan cover an area of 16 square miles. The majority of its buildings were built in the 1000s to 1200s, during the time Bagan was the capital of the First Burmese Empire. It was not until King Pyinbya moved the capital to Bagan in 874 A.D that it became a major city. However, in Burmese tradition, the capital shifted with each reign, and thus Bagan was once again abandoned until the reign of Anawrahta. In 1057, King Anawrahta conquered the Mon capital of Thaton, and brought back the Tripitaka Pali scriptures, Buddhist monks and craftsmen and all of these were made good use of in order to transform Bagan into a religious and cultural centre. With the help of a monk from Lower Burma, Anawrahta made Theravada Buddhism a kind of state religion, and the king also established contacts with Sri Lanka. In the 12th and 13th centuries, Bagan became a truly cosmopolitan centre of Buddhist studies, attracting monks and students from as far as India, Sri Lanka as well as the Thai and and Khmer kingdoms. In 1287, the kingdom fell to the Mongols, after refusing to pay tribute to Kublai Khan. Abandoned by the Burmese king and perhaps sacked by the Mongols, the city declined as a political centre, but continued to florish as a place of Buddhist scholarship.

His father was Kunhsaw Kyaunghpyu, who took the throne of Pagan from Nyaung-u Sawrahan and in turn was overthrown by the sons of Nyaung-u Sawrahan, Kyiso and Sokka-te, who forced Kunhsaw Kyaunghpyu to become a monk. When Anawrahta came of age, he challenged the surviving brother Sokka-te to single combat and slew him. Anawrahta offered to return rulership to his father, who refused and remained a monk, so he took the throne in 1044.

King Anawrahta

He also built the famous Shwezigon Pagoda.

In the end, Anawrahta was successful in his quest, and Theravada Buddhism became the dominant religion in Myanmar within two centuries.

His rule was usurped by a general called Kyanzittha, who allegedly fell in love with Anawrahta's wife to be, the Princess of Mon Kingdom.

Sawlu Min (1077-1084) was the son of King Anawrahta (1044-1077) who established the first Burmese kingdom of Bagan. He was deceived and defeated by his one time friend Ngaramankan who wanted to seize power

King Kyanzittha was king of Bagan from 1084 to 1113. He was a son of King Anawrahta and a lesser queen, and is well-known for building a large number of temples and religious monuments in Bagan, in particular the Ananda Temple. During his youth, Kyanzittha participated in the Thaton campaign to obtain the Tripitaka. He was crowned king after the assassination of King Sawlu, another son of King Anawrahta. Kyanzittha was particularly known for his patronage of the Mon culture; during his reign, he left many inscriptions in Mon, married a Mon princess, and established good relations with the Mon kingdom.

Alaungsithu (1113-1167) during his reign many large temples were also constructed. In particular Thatbyinnyu Temple, Shwegugyi Temple ("Great Golden Cave") is a Buddhist temple built in 1131. The temple itself is built on an expansive brick foundation 3 metres (13 ft) tall. The temple is known for its arched windows, and its history, which is inscribed in two stone slabs in Pali. According to its inscription, the temple was completed in seven months. Dhammayangyi Temple was built in the 1100s. There is dispute as to the date of its construction; it may have been built by either King Narathu or King Alaungsithu. Dhammayangyi Temple is the widest temple in Bagan, and is built in a plan similar to that of Ananda Temple. The temple was never completed.