Editing Sukhothai Kingdom (section)

===Decline and tributary status===
By the beginning of the fourteenth century, Sukhothai controlled the Chao Phraya plain, with spurs West to the [[Hanthawaddy Kingdom]] and South to the [[Nakhon Si Thammarat Kingdom]]. After the death of Ram Khamhaeng, he was succeeded by his son [[Loe Thai]].

Tributary states of Sukhothai began to break away rapidly after the death of Ram Khamhaeng. To the north, [[Uttaradit Province|Uttaradit]] and the [[Lao people|Lao]] kingdoms of Muang Sua and [[Lan Xang#Historical overview|Vieng Chan Vieng Kham]] (present-day [[Vientiane]]) liberated themselves from their Sukhothai overlords. In 1319, Martaban in the west broke away. In 1321, [[Lan Na]] (the successor state to [[Ngoenyang]]) annexed [[Tak Province|Tak]], one of the oldest towns in Sukhothai. To the south, [[Suphannaphum Kingdom]] and [[Nakhon Si Thammarat Kingdom|Nakhon Si Thammarat]] also broke free early in the reign of Loe Thai. Thus, the kingdom was quickly reduced to its former status as merely a local power.<ref name=sri>{{cite web|url=https://archive.today/20241105234239/https://www.sac.or.th/portal/th/article/detail/608|title=ปาไซ-สยามยุทธ์: "พ่อขุนแดนใต้" รบ "แขกสุมาตรา"|date=17 May 2024|trans-title=Pasai-Siam Wars: "King of the South" fights "Indian"|language=th|author=Tongjai Hutangkur|work=[[Princess Maha Chakri Sirindhorn Anthropology Centre]]}}</ref>

In 1323, Loe Thai was succeeded by his cousin, [[Ngua Nam Thum]]. In 1347, he was succeeded by [[Maha Thammaracha I|Li Thai]] (Maha Thammaracha I), the son of Loe Thai. In 1349, armies from [[Ayutthaya Kingdom|Ayutthaya]] invaded the kingdom and forced Sukhothai to become its tributary.<ref name=Coedes/>{{rp|222}} The center of power in the tributary state shifted to Song Khwae (present-day [[Phitsanulok]]). In 1378, [[Maha Thammaracha II|Lue Thai]] (Maha Thammaracha II) had to submit to this new Thai power as a vassal state.<ref name=prince>Chakrabongse, C., 1960, Lords of Life, London: Alvin Redman Limited</ref>{{rp|29–30}} He was succeeded by [[Maha Thammaracha III|Sai Lue Thai]] (Maha Thammaracha III) in 1399.

In 1424, after the death of Sai Lue Thai, his sons Phaya Ram and Phaya Ban Mueang fought for the throne. [[Intharacha (king of Ayutthaya)|Intharacha]] of Ayutthaya intervened and installed Ban Mueang as [[Maha Thammaracha IV|Borommapan]] (Maha Thammaracha IV). When Borommapan died in 1438, [[Borommarachathirat II]] of Ayutthaya installed his son Ramesuan (the future [[Borommatrailokkanat]] of Ayutthaya) as [[Uparaja#Siam (Thailand)|Upparat]] in Sukhothai, a position similar to both that of a [[viceroy]] and an [[heir presumptive]], establishing a form of [[personal union]] and creating the Siamese [[Front Palace]] system. Prince Ramesuan was presumably accompanied by Ayutthayan administrative staff and a military garrison, thus affirming the end of Sukhothai as an independent kingdom.<ref>{{Cite book |author=David K. Wyatt |title=Thailand: A Short History |edition=2nd |publisher=Silkworm Books |year=2004 |page=59}}</ref>