Chaliang (Thai: เชลียง, Chinese: 程良) or Sawankhalok, later known as Si Satchanalai, was a political entity in the upper Chao Phraya Valley in central Thailand.

[1] It was founded in the early 600s by uniting four regional chiefdoms,[2]: 7  with Haritvanlee or Chaliang (นครหริตวัลลีย์) as the center,[3] and became part of the Dvaravati's Lavo.

[4][1]: 28 [5] The term San-lo (三濼) mentioned in Lingwai Daida in 1178[6]: 288, 290  was plausibly referred to Chaliang's new center, Sawankhalok.

[11] In 1157/58, Chaliang was occupied by another Tai monarch from Chawa (ชวา, Muang Sua) or Nam Ou basin.

[1]: 33–34 According to the Northern Chronicle [th], Chaliang was founded in the early 600s by a hermit, Satchanalai (สัชนาลัย; or Anusit อนุสิสส in the Tamnan Mulasasana [th][3]), who united four surrounding chiefdoms and built moats and walls to define the city's boundaries.

In the first era, Chaliang's initial territory included Thung Yung [th] or Wiang Chao Ngo [th] to the northeast and met Sukhothai to the south.

Hermit Satchanalai had four colleagues, each of whom played an important role in the establishment of the ancient kingdoms in modern-day Thailand, as detailed below.

[2]: 21  This marked the beginning of Tai influence over the Chao Phraya Valley, which had been devastated by the invasion of Tambralinga and the Angkor in 928[16][17]: 23 [18] and 1002,[19] respectively.

[20]: 3  At least in 1001, it was potentially ruled by the Tai as it was mentioned as an independent polity centered in Chéng Liáng (程良) in the 4th year of Xián Píng [zh] era 咸平 (1001 CE) in the Chinese Song Shi volume 489 section 248.

[19] These were potentially the reasons for Lavo's decrease in influence over northern polities, which included Chaliang and Sukhothai, in the mid-10th century.

In the late 10th century, after Suphannabhum and Haripuñjaya joined forces and retook Lavapura from the Angkor in 1052[7]: 532 [21]: 42  and moved the capital to Ayodhya in 1080s.

[1]: 25–26 In the 14th century, Sukhothai-Si Satchanalai expanded its territory to the north by destroying and annexed a Tai Yuan's city-state of Mueang Li [th].

[31] Thai chronicles revised during the Rattanakosin period list these four cities as four of the sixteen vassal states of the Ayutthaya Kingdom during the reign of King Ramathibodi I.