The Southeast Asian and southern Indian Ocean region between the eleventh and fourteenth centuries was characterized by fluid relations and dynamic exchanges that connected three main centers of Buddhist learning and practice: Bagan (Burma), northern Thailand, and Sri Lanka. A Buddhist ecumene refers to a geospatial religious and political subsystem that existed within a larger Buddhist commonwealth or world system from the 1000s to 1300s. The idea of the ecumene was manifested in the intellectual environment of fifteenth- to nineteenth-century writers of Burma, Thailand, and Sri Lanka. The beginning of this ecumene coincided with the reign of Anawrahta, an eleventh-century king of Bagan, and cakravartin. The strongest evidence for this ecumene and the king is derived from texts, with support from art history and artifacts.