The Yonok Kingdom, also known as Singhanati, was a semi-legendary polity based along the Kok River, centered at Yonok Nakhon Chaiburi Ratchathani Si Chang Saen (; ) in present-day Chiang Saen district in northern Thailand. Archaeological evidence indicates human habitation in the area since the Neolithic period, though direct links between these early communities and later historical states remain uncertain. According to legend, the region was formerly inhabited by Austroasiatic-speaking peoples and included the earlier legendary polity of .
Legendary accounts state that Yonok was founded by , a son of King Devakala, following a migration into the Chiang Saen area. After its establishment, the kingdom consolidated surrounding settlements and expanded its influence across a broad territory. The narrative emphasizes prolonged stability and the sustained patronage of Buddhism by YonokâÂÂs rulers, alongside interactions with neighboring polities and ethnic groups.
Yonok declined after internal rebellion and was ultimately destroyed by an earthquake in the 5th century CE that submerged its capital. Its population dispersed and formed successor states, including Wiang Prueksa and Ngoenyang, the latter becoming a precursor to the Lan Na Kingdom. Southern offshoots of the Yonok lineage are also associated in later traditions with the early political development of the Chao Phraya Basin.
Archaeological evidence indicates human habitation in the present-day Chiang Saen district as early as the Neolithic period; however, no conclusive evidence has yet been identified that directly links these early communities with either the prehistoric period more broadly or with later historical settlements in northern Thailand. A limited number of prehistoric artifacts have been tentatively associated with the ancient Haripuñjaya Kingdom, though further historical and archaeological investigation is required to substantiate such connections. According to legendary accounts, prior to the establishment of Singhanavati, the region was inhabited by Austroasiatic-speaking populations, particularly the Khmu and Lawa peoples. The principal preexisting polity, situated on the left bank of the Mekong River opposite present-day Chiang Saen, is described as the legendary kingdom of . Its ruling lineage is said to have later migrated to Umongasela (), in what is now the Fang area, following the submergence of into the Mekong River.
According to legend, Yonok was founded by , the younger son of King Devakala (), ruler of Ho people () at Rajgir. Thai scholars have identified Rajgir with modern Dali in Yunnan, a region which, during the period in question, lay within the sphere of influence of the ' ()âÂÂa multi-tribal alliance associated with branches of the Di-Qiang peoplesâÂÂas well as the ancient state of Tsen (8thâÂÂ2nd century BCE), and the latter ancient tribal confederation known as Ngai-Lao or Ailao (5th century BCEâÂÂ77 CE). In the late 1st millennium, Six ZhaoâÂÂa confederation of six regional lordships, were formed, five of which are recorded as being composed of Tai speaking Lao or Lao-related tribal groupsâÂÂand later became Nanzhao.
While his elder brother, Bimbisara, was designated crown prince, Singhanavati and his 28 siblings were instructed by their father to depart the kingdom and seek territories in which to establish their own domains. At the age of 18, Singhanavati, accompanied by one princess and a reported following of 100,000 people, migrated southeastward, crossing the Sarapu River () and several other waterways. The journey is said to have taken four months, after which the group reached the area corresponding to present-day Chiang Saen. At that time, the site was described as containing the ruins of a pre-existing polity identified in legend as the Kingdom of . Singhanavati subsequently established his domain there. Based on the chronological information preserved in the legend, the foundation of Yonok has been calculated to have occurred in 637 BCE.
Under âÂÂs rule, Yonok is recorded as having launched a military campaign against Umongasela, a successor polity of located to the southwest, which was ultimately annexed. The first five years of his reign are characterized as a period of political consolidation, during which efforts were made to unify the pre-existing settlements of the region. The extent of his authority is described as reaching the Nam Tae River () to the east, the Maenam Kong () to the west, met the Nong Sae region () to the north, and Lavarath (; ) near the mouth of the Ping River to the south. Thai scholars have identified these toponyms respectively with the regions of the Black River, the Salween River, Erhai Lake, and the Chao Phraya River basin.
Following this phase of influence expansion, âÂÂs reign is portrayed as a period of stability, with no recorded internal or external conflicts. The text further emphasizes that the duties of Singhanavati and several of his successors were primarily associated with the promotion and maintenance of Buddhism. This religious orientation is particularly evident during the reigns of Achutraraj and his son Mangrai Naraj. Additionally, royal intermarriage with Lawa communities at Doi Tung is recorded as having occurred during the reign of the third monarch, Achutraraj ().
After a prolonged period of relative peace and deep entrenchment in Buddhist institutions, Yonok, during the reign of Bhrngaraja, experienced a major political upheaval precipitated by the uprising of the vassal ruler of Umongasela. Owing to his youth, the Khom king of Umongasela is said to have led a military campaign against Yonok in 357 CE. As a result, Bhrngaraja was overthrown after a reign of only two years and subsequently exiled to Wiang Si Thuang (; present-day Wiang Phang Kham, Mae Sai district), a tributary polity of Yonok. During his period of exile, he fathered two sons, Duhkhita and Phrom. The latter later achieved a notable military success by reclaiming Yonok from Khom control in 397 CE and restoring the throne to his father. Phrom is further credited with pursuing the Khom forces southward as far as the area of present-day Kamphaeng Phet. Moreover, he established a new town as a defensive outpost in the former Umongasela area to prevent enemy incursions, renaming it Chai Prakan, to which he returned to govern following the conclusion of these campaigns.
The last king of the Singhanati Kingdom was Maha Chaichana (). During his reign, Yonok was submerged beneath Chiang Saen Lake as a result of an earthquake in 467. The survivors, led by Khun Lung, subsequently migrated eastward to settle at Wiang Prueksa. The remaining principalities, comprising fourteen chiefdoms, formed an assembly to select new rulers, establishing an elective system of governance that endured for 93 years. The legend also records a series of seismic events during the reign of , the founding monarch of Yonok. These accounts refer to four earthquakes in total, with the most severe allegedly occurring in the 57th year of his reign.
Earlier, in 444 CE, Chaiyasiri, ruler of Chai Prakan and son of Phrom, faced a month-long invasion by the Mon kingdom of Thaton. Unable to retreat to Yonok due to flooding and military disadvantage, he led roughly 100,000 families south along the Yom River to the southern edge of Yonok in the Chao Phraya Basin, founding a settlement later identified as Kamphaeng Phet. Chaiyasiri ruled there until his death in 457 CE, after which no further records of this southern lineage survive. Two centuries later, Chinese sourcesâÂÂthe Tang Huiyao and Cefu YuanguiâÂÂmention this area as the location of the Duà  Miè Kingdom, situated west of Tou Yuan with a proposed center at Lopburi; it reportedly comprised 30 cities, remained independent of other states, had a substantial population, and practiced Buddhism. By the mid-8th century, the area came to be known as Indaprasthanagara, with Padumasuriyavamsa claimed in later traditions as its first Siamese monarch, from whom the lineage of Visnuraja of Phraek Si Racha, a progenitor of the Sukhothai and Ayutthaya monarchs, further asserts descent.
Following the fall of Yonok, records from 638 indicate the emergence of highland communities at Doi Tung, previously a tributary of Yonok, under the leadership of Lao Chakkaraj, who later became the ruler of Wiang Prueksa in 648. Lao Chakkaraj subsequently reconstructed Wiang Phang Kham and renamed Hiran, an act regarded as marking the beginning of the Ngoenyang Kingdom. This polity continued through successive generations and culminated in the founding of the Lan Na Kingdom at the end of the 13th century.
During this same period, to the south of Wiang Phang Kham, another principalityâÂÂHaripuñjayaâÂÂwas established in the Ping River valley in 629 by the legendary figure Sudeva. He later invited the Mon princess Camadevi from the southern kingdom of Lavo to rule the city in 662, an event that marked the expansion of LavoâÂÂs influence into northern regions.
Owing to Manit VallipodomâÂÂs interpretation in 1973, which equated the Tertiary Era mentioned in the legend with the Chula Sakarat era, the later monarchs of the Singhanavati dynasty, particularly Chaiyasiri, were consequently dated to the 10th century CE. As the legend states that Chaiyasiri relocated to the Chao Phraya River valley, this revised chronology led earlier Thai scholars to identify him as the progenitor of Uthong, the first monarch of the Ayutthaya Kingdom, by equating him with the legendary ruler or with Phanom Thale Sri of the Phetchaburi dynasty. In traditional accounts, each of these figures is recorded as having a son named UthongâÂÂnamely, Uthong III of the Suphannaphum dynasty in the case of , and Uthong II of the Lavo dynasty in the case of Phanom Thale Sri. This equation of Chaiyasiri with Phanom Thale Sri further led to Chaiyasiri being identified as the founder of the Phrip Phri Kingdom.
These assumptions were later demonstrated to be erroneous. Phanom Thale Sri is explicitly identified as an elder son of Anuraja, a ruler of an early Siamese polity in the Phraek Si Racha region, by the Ayutthaya Testimonies, while Uthong of Ayutthaya is now securely attested as a son of Baramaraja and must be regarded as a distinct historical figure, separate from the sons of and Phanom Thale Sri. Moreover, VallipodomâÂÂs equation of the Tertiary Era with the Chula Sakarat was subsequently challenged by later scholars, notably Phiset Chiachanphong, who convincingly argued that the Tertiary Era should instead be identified with the Shaka era. This reinterpretation places the lifetime of Chaiyasiri in the 5th century CE rather than the 10th century.
The narrative preserved in the original text employs multiple calendrical era systems, a feature that has given rise to significant interpretative difficulties among earlier scholars. Most notably, Manit Vallipodom equated the Tertiary Era referenced in the text with the Chula Sakarat era. This identification resulted in the placement of the later Singhanavati monarchs in the 11th century CE, thereby creating a chronological overlap between territories attributed to the Singhanavati lineage and those known to have been under the control of Ngoenyang during the same period. Furthermore, Vallipodom introduced an additional ruler, King Mang Saen (), in order to bridge perceived gaps in the dynastic sequence between Mang Sing () and Mang Som (); however, this figure is not attested in the original text.
In contrast, the Secondary Era is explicitly defined in the text in a manner that closely corresponds to the Buddhist Era. This identification is supported by the statement that its second monarch, Phanthati (), died in the same year as the Buddha, after which the year count recommenced at one with the accession of the third monarch, Achutraraj (). This chronological framework is applied consistently throughout the reigns of Geng, Ping, Kom, and Duhkhita, for whom the regnal years recorded in the text correspond directly to Buddhist Era dates cited in the same passages.
With regard to the Tertiary Era, Phiset Chiachanphong has proposed that it should instead be identified with the Shaka era. When these two propositionsâÂÂnamely, the equation of the Secondary Era with the Buddhist Era and the identification of the Tertiary Era with the Shaka eraâÂÂare applied conjointly, the resulting chronology remains internally consistent. In particular, during the reigns of King Fan and King Wan, the text records the abandonment of the earlier era system and the institution of a new one; when these dates are converted into the Common Era, the transition occurs without any chronological discontinuity. However, this presupposition results in an almost century-long temporal gap between Yonok and its successor polity, Wiang Prueksa, a conclusion that contradicts the context preserved in the original text, which suggests a seamless transition.
The apparent discontinuity described above is more plausibly attributable to scribal errors arising from successive copying, as is clearly demonstrated by inconsistencies in the regnal chronology. According to the text, Maha Wan succeeded Duhkhita directly; however, while the terminal year of DuhkhitaâÂÂs reign is recorded as 349, that of Maha Wan is given as 469, implying an implausible interval of more than a century between two successive reigns. This discrepancy is further contradicted by the narrative itself, which explicitly states that Maha Wan reigned for only 21 years. The problem becomes even more explicit in the case of Maha Chaichana, who is said to have succeeded Maha Wan directly, yet whose terminal year is recorded as 376. This date not only precedes the terminal year assigned to Maha Wan but also represents a chronological regression within an otherwise linear sequence of reigns, rendering the regnal chronology internally incoherent. If the terminal dates of Maha WanâÂÂs reign and that of Chaiyasiri, both recorded as ending in 469 SE, are accepted as accurate, the apparent chronological hiatus between Yonok and its successor polity, Wiang Prueksa, disappears. This adjustment, however, would require the reigns of the remaining monarchs to be shifted forward by nearly a century relative to the dates preserved in the text.
The following section enumerates the rulers of the Yonok Kingdom and the durations of their reigns.
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