Pra Poa Noome Thele Seri

According to Du Royaume de Siam and the Instructions Given to the Siamese Envoys Sent to Portugal (1684), Phra Phanom Thale Seri relocated the political center from Tasoo Nacora Louang to Soucouttae/Locontàï circa the 1150s. Shortly thereafter, he, together with his younger brother, Uthong I (also known as Soi La, ), and approximately 50,000 attendants, moved southward into the western Menam valleys, where they reestablished Phrip Phri. The year of this relocation is variably reported as 1155; In 1205, his son, Uthong II, is said to have asserted dynastic authority by claiming the throne of Xiān's Ayodhya. The Ayutthaya Testimonies present an account of an early Siamese monarch, Intharacha (), whose narrative exhibits striking parallels with that of Phra Phanom Thale Seri, ruler of Phrip Phri. According to the text, Intharacha succeeded his relative, Jatiraja (), as ruler of either Mueang Phraek's Singburi () or Jayasimhapuri (), before relocating southward to establish his authority at Phetchaburi. His reign is described as extending over thirty-five years. The text further identifies his brother, Uthong, as having assumed rulership of Singburi following Intharacha’s departure, while his son—also named Uthong—later ascended the throne of Ayodhya in 1205. This undertaking resulted in the establishment of the and facilitated the southward expansion of Siam influence across the Kra Isthmus. While succession in this polity remained patrilineal, the confirmation of a ruler required formal appointment from Ayodhya, reflecting the continuing political linkage between the northern and southern domains. During his reign in the western valley, a polity identified as Xiān dispatched a tributary mission to Đại Việt in 1182. ==Indaprasthanagara, Chen Li Fu, and the emergence of Ayutthaya==

According to the Ayutthaya Testimonies and the Chronicle of Padumasuriyavamsa, Sukhothai had been a vassal polity of Indaprasthanagara since the 8th century. Thai scholarship has long tended to equate Indaprasthanagara with Angkor, an interpretation that has reinforced the assumption that Sukhothai was a vassal of the Angkorian state. This period coincides with the consolidation of authority by Pra Poa Noome Thele Seri in the same region. Following this transition, Xiān (), which had maintained trade relations with Đại Việt since 1149 during the reign of Pra Poa Noome Thele Seri's father Anuraja, appears with increasing frequency in Chinese sources, first recorded as xiān in 1278 and earlier as san-lo () in 1178. It is also notable that before 1200, Xiān maintained trade relations with Đại Việt and established a trading post at Yún tún (), modern Vân Đồn. This trading post operated near areas under Chinese imperial authority. However, Chinese sources do not record the presence of Xiān merchants until 1278. This absence in earlier Chinese records strengthens the theory that the group later identified as Xiān in Chinese texts may have evolved from or been connected to Chen Li Fu. ==Genealogy==

Thai scholars once posited that the brothers Uthong I and Phra Phanom Thale Seri were princes of Chaiyasiri, identified with a monarch of Singhanavati in the northern region who may have migrated to Nakhon Thai during the 11th century. However, this hypothesis, which also underpins the outdated claim that Ramathibodi I—the first sovereign of the Ayutthaya Kingdom and a supposed descendant of Phra Phanom Thale Seri —originated from Mueang Uthong, has been refuted by subsequent scholarly inquiry. The Ayutthaya Testimonies presents an alternative account, stating that Uthong I and Phra Phanom Thale Seri were the sons of Anuraja , whose lineage purportedly succeeded the Padumasuriyavaṃśa dynasty in the polities of Mueang Phreak, Chai Nat, and Sing Buri. Nevertheless, the narratives concerning Sing Buri and Jayasimhapuri, as conveyed in the text, appear to have been interwoven or conflated. The following account outlines the genealogy of Phra Phanom Thale Seri as preserved in the Ayutthaya Testimonies, while additional information regarding his descendants is provided in the Northern Chronicle and the Nakhon Si Thammarat Chronicle. ==Interpretations on Tasoo Nacora Louang==

The precise identification of Tasoo Nacora Louang or Yassouttora Nacoora Louang remains a matter of scholarly debate. It is unclear whether this political center corresponds to Lavapura of Lavo or to Yaśodharapura of Angkor or a village in modern Uttaradit province. However, polities bearing names closely resembling Yassouttora Nacoora Louang are attested in Thai sources such as the Legend of Mueang Nakhon Chai Si () and the Legend of Phra Prathon Chedi (). These narrative, whose associated events are traditionally dated to 679 CE, describe that Nakhon Luang () and Yassodhon () as distinct yet adjacent polities. The same sources further record that Balidhiraja of Sukhothai, who was the son of Kalavarnadisharaja (king of Lavo), was originally from Nakhon Luang. the earliest Siamese ruler mentioned in Du Royaume de Siam. Ayodhya, which earlier was under Chen Li Fu, which has been proposed to have had connections with the Mahidharapura dynasty of the Phimai region and Angkor. Taken together with the Angkorian-influenced architectural style evident in the region associated with Pra Poa Noome Thele Seri, these circumstances suggest that he maintained some form of political or dynastic relationship with the Lavo–Angkorian ruling sphere and consequently strengthens the possibility that Tasoo Nacora Louang/Yassouttora Nacoora Louang may correspond to Lavapura. Alternatively, based on phonetic similarity, Tasoo Nacora Louang has been identified by some scholars with the village of Tha Sao (), with Tasoo corresponding to Tha Sao and Nacoora Louang understood as referring to a "capital" or "royal city". This location is situated near modern Uttaradit, where several archaeological sites—most notably the ruins at —have been identified. The same area has also been proposed as the region from which a Tai ruler named Chaiyasiri migrated to establish Mueang Tri Trueng () following the fall of Yonok Chiang Saen, a polity that some scholars have identified with Tchai Pappe Mahanacon (), a city mentioned in 17th-century European sources. Moreover, Saen Pom, associated with Mueang Tri Trueng, is said to have moved southward and established his authority at Thepnakhon (), which has been proposed to correspond to Suphannabhum. ==Notes==