Pyu city-states
Beikthano ( ) situated in the irrigated Minbu region (near present-day Taungdwingyi) with direct land access to the well-watered Kyaukse plains to its northeast, is the oldest urban site so far discovered and scientifically excavated site. Its remains—the structures, pottery, artefacts, and human skeletons—date from 200 BCE to 100 CE. Named after the Hindu god Vishnu, the city may be the first capital of a culturally and perhaps even politically uniform state in the history of Burma. It was a large fortified settlement, measuring approximately 300 hectares inside the rectangular (3 km by 1 km) walls. The walls and fortifications along it measured six meters thick, and are radiocarbon dated to a period between 180 BCE and 610 CE. Like most subsequent cities, the main entrance of the walls led to the palace, which faced east. Stupas and monastic buildings have also been excavated within the city walls.
Prehistory of Myanmar
The Mon people of Haribhunjaya and Dvaravati kingdoms in modern Thailand may have entered present-day Lower Burma as early as the 6th century CE. According to mainstream scholarship, the Mon had founded at least two small kingdoms (or large city-states) centred on Pegu (Bago) and Thaton by the mid 9th century. The earliest external reference to a Lower Burma "kingdom" was in 844-848 by Arab geographers. The Mon practised Theravada Buddhism. The kingdoms were prosperous from trade. The Kingdom of Thaton is widely considered to be the fabled kingdom of Suvarnabhumi (or Golden Land), referred to by the tradesmen of Indian Ocean.