Dvaravati refers to a cultural and political network of early historic polities that flourished in the present-day central Thailand from approximately the 6th to the 11th century; however, archaeological evidence suggests that the cultural developments associated with Dvaravati began several centuries earlier, often described as a Proto-Dvaravati phase. It is tentatively regarded as a successor to the polity known in Chinese sources as Lang-chia or Lang-ya-hsiu. Chinese Buddhist accounts from the mid-7th century describe a Buddhist kingdom called To-lo-po-ti, located west of Isanapura (Cambodia), east of Sri Ksetra (Burma), and north of Pan Pan. Its northern frontier bordered Jiā Luó Shě Fú (迦逻舍佛), identified with Canasapura, which covered the upper Mun-Chi basin in present-day northeastern Thailand and Si Thep in the Pa Sak basin in central Thailand. Dvaravati is recorded to have sent embassies to the Chinese court in 583, around 605–616, in 638, 640, 643, 647, and 649.