Si Inthrathit (Thai: ศรีอินทราทิตย์, pronounced[sǐːʔīn.tʰrāː.tʰít]; also spelt Śrī Indrāditya) was the first king of the Sukhothai Kingdom, a historical polity in what is now Thailand. He reigned from 1238 until around 1270 and is credited as the founder of the Phra Ruang dynasty, regarded as the first historical Siamese dynasty.
Born Bang Klang Hao and ruler of Mueang Bang Yang, he took Sukhothai from Khom Sabat Khlon Lamphong in 1238 in alliance with his brother-in-law Pha Mueang of Mueang Rat. Pha Mueang declined the throne and invested him as ruler instead, passing on his own Khmer-conferred title of Si Indraditya. The episode has long been read as the liberation of Sukhothai from Khmer rule and the founding of an independent Tai kingdom; more recent work treats it as a contest between local lords who both held Khmer honours.
Biography
Origin
Before his accession he was known as Pho Khun Bang Klang Hao (Thai: พ่อขุนบางกลางหาว), read as "the lord who rules the sky".[citation needed]Bang Klang Hao was born to Nang Nak (นางนาค), a queen consort of Candraraja,:15 who relocated the seat from Kamphaeng Phet to Sukhothai. Sirisudhārājadevī (สิริสุธาราชเทวี), a consort of Suryaraja, was his grandmother.:11 The same testimony gives him a younger brother, likewise styled Phra Ruang, and a sister, Suvaṇṇadevī (สุวรรณเทวี).:15,17 The Legend of Sawankhalok adds an elder brother, Phra Ruang III, who ruled Mueang Fang (เมืองฝาง), identified with Sawangkaburi[th].:28
The Ayutthaya Testimonies delineates his dynasty as the descendants of King Phatumsuriyawong, whom certain historians have identified with the Khmer monarch Suryavarman II. However, such an assumption appears chronologically inconsistent when juxtaposed with the genealogical account of an early Siamese royal line that ruled in the Phraek Si Racha region. The first monarch of this lineage, Visnuraja, who likewise claimed descent from King Phatumsuriyawong,:37–8 is recorded to have been born in 950 CE.
Sukhothai and Indapraṣṭhanagara
In the late 12th century, the Angkorian Empire expanded northward under the Mahidharapura dynasty, reasserting its authority over Lavo and extending control into the central basin. By 1180 CE, the domain of Phraek Si Racha region had come under a royal house that may have been connected to Angkor and was later re-established as Chen Li Fu.:18 During this period, Candraraja, a descendant of the Phrak Si Racha line and father of Si Inthrathit, ruled at Kamphaeng Phet before transferring the royal seat to Sukhothai.:11
Initially, Candraraja continued to pay tribute to Indaprasthanagara,:15–6 a polity that early scholars have attempted to identify with Angkor,:8:1–3 although the Ayutthaya Testimonies place it to the east of Sankhaburi.:5–6Michael Vickery rejected the Angkorian identification in 1995 on philological grounds, holding that the sruk indraparāś of the Angkorian inscriptions denotes a village or district and not a capital.:191–2 Under the direction of Si Inthrathit, however, these payments were discontinued,:15–6 perhaps as a response to increasingly burdensome taxation. This led to armed conflict between Sukhothai and Indaprasthanagara, in which Si Inthrathit commanded the Sukhothai forces to victory, after which Indaprasthanagara did not again interfere in Sukhothai's affairs. The confrontation has been placed at about 1208 and read as the point at which Sukhothai became independent in fact.:15–6
Accession in 1238
After the victory over Indapraṣṭhanagara, Si Intharathit came to rule Mueang Bang Yang, in the present-day Nakhon Thai district, which had previously served as the power base of his kinsman, Pra Poa Noome Thele Seri. During his tenure there, Si Intharathit was potentially supported by Tai Yuan refugees who had fled to the region following the fall of Yonok.:30 He also married Nang Sueang[th], a Tai Lueang (ไทเลือง) princess and daughter of Sri Naw Nam Thum, the ruler of Mueang Rat (เมืองราด), situated in either modern Lom Sak district, to the east of Mueang Bang Yang, or at the ancient Mueang Thung Yang[th] in modern Uttaradit province.:54–9 This Tai Lueang polity subsequently expanded its sphere of influence into Mueang Chaliang, which had been under the mixed Monic–Chinese Haripuñjaya dynasty, during the waning reign of Rajadhiraj II in the early 13th century.:15–6
Candraraja died in 1214.:17 What followed is given differently in the sources. The Ayutthaya Testimonies have Si Inthrathit succeed him directly,:17 whereas on the reading of the Wat Si Chum Inscription Sukhothai passed instead to the Mon ruler E Daeng Phloeng.:115
Pho Khun Bang Klang Hao was then declared king at Sukhothai, taking a regnal name of Sanskrit origin, Si Inthrathit, translated from Adityan Indra. Baker and Pasuk give the name a nearer source, as the Khmer-bestowed title of Pha Mueang, transferred to him when Pha Mueang declined the throne and invested him instead.:35 Wyatt offers a reason for the transfer, on the premise that Angkor held the region and that Pha Mueang had sworn an oath to its ruler while Bang Klang Hao had not. By handing over the city and the title together, Pha Mueang escaped the consequences of breaking it. The same reasoning gives Wyatt a later date, about 1243 rather than 1238 or 1220, since Bang Klang Hao was the father of Ram Khamhaeng, who was reigning in the 1290s.:52–53 The rank that came with the title was not peculiar to the two men. Chinese records of the same decades give kamrateng to the rulers of Chen Li Fu and Phrip Phri as well as to those of Sukhothai and Lavo, so that it marks a class of ruler rather than a singular appointment. Wyatt's wider argument turns on relics, which were believed to resist the unworthy, so that a ruler who handled one was demonstrating the merit that entitled him to rule.:19,34,62–63 His skill and bravery greatly impressed the people of the kingdom, who thus conferred him the title Phra Ruang (glorious prince). This title was given to all subsequent rulers of Sukhothai, thus giving rise to the first Thai royal dynasty of Phra Ruang.
Readings of 1238
The readings of 1238 differ first over who the defeated man was. The account long received, set out by Griswold and Prasert na Nagara, makes Khom Sabat Khlon Lamphong the commander of a Khmer garrison, so that the campaign against him was the liberation of Sukhothai from Khmer suzerainty and the founding of an independent kingdom under a Tai dynasty. Baker and Pasuk also argue that the ethnic framing and the idea of liberation were both imported from a later era, and read the inscription as recording a victory by one local lord associated with Angkor over another holding a Khmer title; on their account Pha Mueang, who invested Bang Klang Hao, had himself received a title, a regalia sword and a princess in marriage from the ruler at Angkor.:35 Wyatt had set the ethnic framing aside in 2001, holding that the line between the two sides was religious and cultural and that the two men were acting on home ground rather than as invaders, though his own account keeps Sukhothai an Angkorian possession.:54,62 For the reign of Jayavarman VII, 1181 to 1218, Baker and Pasuk report that no temple-endowment inscriptions of the Angkorian provincial type have been found on the Chao Phraya plain and that his hospital foundations reach no further west than Prachin Buri.:22–4 Wyatt's own survey of the dated inscriptions of 1168 to 1219 gives the same result for Lopburi and Grahi, with his caution that the absence is not conclusive.:50–51 Saipan Puriwanchana adds a folklore reading of the same episode. She takes from Sukanya Sutchaya a catalogue of Phra Ruang motifs in which the driving out of the Khom is carried by the Phongsawadan Nuea, the Culayuddhakaravamsa and the Kham Hai Kan Chao Krung Kao.:154 On her account that motif was absorbed into the record of Bang Klang Hao's accession, so that a figure of legend took on the marks of a hero of national history.:155,164
Reign and succession
Si Inthrathit and his queen, Sueang, had three sons. Their eldest son died at a young age, while the second was named Ban Mueang. Their third son defeated an opponent in mounted combat on elephants. In commemoration of this feat, he named his youngest son Ram Khamhaeng (Rama the Bold). The inscription identifies the opponent as Khun Sam Chon, ruler of Mueang Chot, who had attacked Tak.:134 Si Inthrathit died around 1270 and was succeeded by his son Ban Mueang.
↑The reigns of the monarchs belonging to this lineage were retroactively reconstructed on the basis of the documented accession date of a later ruler, Fang-hui-chih, who governed Chen Li Fu, a polity likewise centred in the Phraek Si Racha region, from 1180 to 1204 CE, as attested in contemporary Chinese sources.
↑Phra Muninthanuwat (Munin Suntharo) (1973). ตำนานเมืองสวรรคโลก[Legend of Sawankhalok] (in Thai). Bangkok: Liang Chiang Tham Prathip Printing House.
↑Thepthani Administration (Chalerm), Phra. (1965). The Chronicles of the Thai Nation: The Origins of the Nation from Ancient Times. Compiled by Phra Boriya Thepthani, Governor of Pathum Thani, Lop Buri, Trat, and the Governor of Nonthaburi and Prachuap Khiri Khan Provinces (complete in 2 volumes). Bangkok: Office of S. Thammaphakdi. Page 133.
↑Walailak Songsiri (2025). ในดินแดนแห่งเจนลีฟูและตามหารากเง้าพระอาจารย์ธรรมโชติ[In the land of Cenlifu and searching for the roots of Master Thammachot] (in Thai). Lek-Prapai Viriyaphan Foundation.
↑Srisak Vallipodom (19 July 2021). "กำเนิดสุโขทัย รัฐแรกเริ่มของชนชาติไทยในสยามประเทศ"[The origin of Sukhothai, the first state of the Thai people in Siam Pradesh]. muangboranjournal.com (in Thai). Retrieved 14 December 2024.{{cite web}}: CS1 maint: deprecated archival service (link)
↑Coedès, George (1968). Walter F. Vella (ed.). The Indianized States of Southeast Asia. Translated by Cowing, Susan Brown. University of Hawaii Press. ISBN978-0-8248-0368-1.
↑Griswold, A. B. & Prasert na Nagara (1971). “The Inscription of King Rama Gamhen of Sukhodaya (1292 A.D.).” Journal of the Siam Society, 59 (2): 179–246.
↑Coedès, George (1968). The Indianized States of Southeast Asia. Honolulu: University of Hawaii Press. pp.180–183.
↑"Ramkhamhaeng". Encyclopaedia Britannica. Encyclopaedia Britannica. Retrieved 23 October 2025.
↑Wongthes, Sujit (1983). สุโขทัยไม่ใช่ราชธานีแห่งแรกของไทย [Sukhothai Was Not the First Royal Capital of the Thai]. Sinlapa Watthanatham special issue (in Thai). Bangkok: Sinlapa Watthanatham. ISBN974-8350-36-3.
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