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.
History of Myanmar
The Pyu entered the Irrawaddy valley from present-day Yunnan, c. 2nd century BCE, and went on to found city-states throughout the Irrawaddy valley. The original home of the Pyu is reconstructed to be Qinghai Lake in present-day Qinghai and Gansu. The Pyu were the earliest inhabitants of Burma of whom records are extant. During this period, Burma was part of an overland trade route from China to India. Trade with India brought Buddhism from South India. By the 4th century, many in the Irrawaddy valley had converted to Buddhism. Of the many city-states, the largest and most important was the Sri Ksetra Kingdom southeast of modern Pyay, also thought to once be the capital city. In March 638, the Pyu of Sri Ksetra launched a new calendar that later became the Burmese calendar.