Mon tradition holds that Thaton was the heart of Suvannabhumi, the "Golden Land," a name also claimed by parts of Lower Thailand. According to the chronicles, the kingdom was founded during the time of the Buddha himself, in the sixth century BCE, and was ruled by a dynasty of 59 kings. The historical reality is more modest but no less remarkable. The kingdom likely coalesced sometime in the ninth century, as Mon people migrated into Lower Burma from what is now northern Thailand. Centered on the city of Thaton, it functioned as a city-state that punched far above its weight through trade and religion. Merchant ships connected Thaton directly to South India and Sri Lanka, carrying goods and ideas across the Bay of Bengal. Through these maritime links, Thaton became one of the primary centers of Theravada Buddhism in all of Southeast Asia, a spiritual conduit between the Buddhist heartlands of Sri Lanka and the kingdoms of mainland Southeast Asia.

Archaeologists have identified several sites attributed to the Thaton kingdom, though the work is far from complete. Suvarnabhumi City in Bilin Township, also called Winka Old City, contains 40 elevated mounds of which only four have been excavated. Nearby walled sites at Kyaikkatha and Kelasa have been dated as early as the sixth century, suggesting organized urban settlement in Lower Burma centuries before Thaton's recorded fall. Other urban centers in Myanmar were already Buddhist at this time: the Sri Ksetra kingdom near modern Pyay shows evidence of Buddhist practice as early as the fifth century. Yet the archaeology of Lower Burma remains frustratingly incomplete. The delta itself complicates the picture. Sedimentation has extended Myanmar's coastline by roughly three miles per century, which means the geography that Thaton's merchants knew bears little resemblance to what exists today. Some scholars argue that in Thaton's era, the sea reached too far inland to support the kind of large population that chronicles describe.

Traditional Burmese and Mon accounts agree on the essential narrative: the Pagan kingdom, expanding from Upper Burma under King Anawrahta, besieged Thaton and took it. The chronicles record the precise date of Manuha's surrender as 17 May 1057, the eleventh waxing of Nayon in the Burmese calendar year 419. What followed was not mere conquest but cultural absorption on a massive scale. Between 1050 and roughly 1085, Mon craftsmen and artisans built the temples and monasteries that made Pagan one of the great architectural achievements of the medieval world. The Mon script, already a mature writing system, was adopted and adapted into what became the Burmese alphabet. The earliest evidence of written Burmese dates to 1058, just one year after the fall of Thaton. From a geopolitical standpoint, Anawrahta's conquest accomplished something else: it checked the westward advance of the Khmer Empire along the Tenasserim coast, establishing Pagan as the dominant power in the region.

Not all scholars accept the traditional narrative. Some modern researchers argue that Mon influence on Upper Burma after the conquest has been greatly exaggerated, a post-Pagan legend that grew in the telling over centuries. According to this view, Lower Burma lacked a substantial independent polity before Pagan's expansion, and the cultural transfer flowed not from a conquered Mon kingdom but from direct contact with India and Sri Lanka. Thai sources, specifically the Northern Chronicle, support a different version of Thaton's pre-conquest history, claiming the coastal region had been under the authority of the Monic Mueang Chaliang from the reign of Arunaraja in the 950s. The debate matters because it shapes how we understand the origins of Burmese civilization itself. Was Pagan's cultural flowering built on the foundation of a conquered Mon culture, or did it develop through independent contact with the wider Buddhist world? Whatever the answer, all scholars accept one thing: during the eleventh century, Pagan established authority over Lower Burma, and this conquest opened a period of cultural exchange that produced one of Southeast Asia's most extraordinary civilizations.

The city of Thaton still exists, a modest town in Mon State on the road between Yangon and Mawlamyine. It does not advertise its ancient significance loudly. The archaeological sites remain largely unexcavated, their secrets locked beneath mounds that local farmers cultivate without knowing what lies below. The Shwezayan Pagoda in Thaton is among the few standing links to the kingdom's Buddhist heritage, though even its dating is disputed. What Thaton left behind is less visible than Pagan's thousands of temples but arguably more fundamental. The Mon script gave Burma its alphabet. Mon Theravada Buddhism became the dominant faith of the entire region. Mon artistic and architectural traditions shaped what Pagan built and what Pagan's successors inherited. The conquered kingdom shaped its conqueror more profoundly than any military victory could, a legacy written not in stone but in the script itself.