Sindhob Amarin (), also known by the abbreviated title Phraya Kreak (), emerges as a monarch of the 10th century in mainland Southeast Asian historiography, principally attested in the Northern Chronicle, the Ayutthaya Testimonies. and the '. These sources identify him as a ruler exercising authority over the ancient polities of the Phraek Si RachaâÂÂAyodhya historical region, a strategic zone within the central Menam Basin. While the Ayutthaya Testimonies do not explicitly record the dates of his reign, a chronological reconstruction derived from the narrative framework of the Northern Chronicle suggests that Sindhob Amarin's rule extended approximately from 937 to 996 CE. The polity of Lavo is also said to have come under his authority during this period. Moreover, his reign also associated with the episode of Sricandradhipati, who, after being ordered arrested by the king of Indaprasthanagara, fled and was subsequently offered the throne of Sukhothai in 959 CE.
This reconstructed reign period partially overlaps with that of Sudhammaraja, another ruler associated with Phraek Si Racha, whose reign is estimated to have lasted from 922 to 957 CE. The apparent overlap can be plausibly reconciled by the testimony of the Ayutthaya Testimonies, which records that Sudhammaraja subsequently relocated northward to establish Phitsanulok as his new political seat. On this basis, it is reasonable to infer that Sindhob Amarin's accession coincided with, or immediately followed, Sudhammaraja's departure from Phraek Si Racha.
No extant source explicitly records the dynastic relationship between Sindhob Amarin and his predecessor, Sudhammaraja. Nevertheless, his reign corresponds chronologically with a period during which Tambralinga exerted influence over the lower Menam Basin, approximately from 927 CE to the mid-10th century, with Lavo functioning as a principal regional power center. The SihinganidÃÂna further records that in 1500 BE (958/59 CE) political authority associated with Sukhothai encountered that of Nakhon Si Thammarat (Tambralinga) to the south.
Sindhob Amarin is also found in the regnal lists of Ayutthaya reconstructed by the Burmese compilers of the Ayutthaya Testimonies. However, these Burmese-derived king lists have subsequently been interpreted by Thai scholars as containing numerous errors and chronological inconsistencies when compared with other extant sources.
In 927 CE, Lavo is recorded as having come under the authority of King Sujita of Tambralinga. Three years later, he was succeeded by his son, Kampoch, who is said to have conducted several campaigns against polities in the Menam basin, including Haripuñjaya. During one retreat from Haripuñjaya to Lavo, Kampoch reportedly led his forces to attack Nakaburi (), but the attempt was unsuccessful.
During the reconstructed reign of Sindhob Amarin (937âÂÂ996 CE), Lavo is described in the Northern Chronicle as a tributary of Indaprasthanagara. In the same source, Sricandradhipati, originally named Ruang and identified as a commoner of Lavo, fled after being ordered arrested by the ruler of Indaprasthanagara and was subsequently offered the throne of Sukhothai in 959 CE. The sources do not specify when Indaprasthanagara assumed control over Lavo from Tambralinga, and Nakaburi remains unidentified in relation to other contemporary polities.
The Northern Chronicle further provides a narrative backdrop that illuminates Sindhob Amarin's military campaign. According to the chronicle, in 944 CE, a nobleman from Mueang Bang Pan (; in present-day Phran Kratai district) named Bhuddhasagara () migrated southward and was subsequently enthroned as ruler of Mueang Wat Derm (), later known as Ayodhya, located on the eastern bank of the Pasak River opposite the site of modern Ayutthaya Island. In 974 CE, Bhuddhasagara's son succeeded to the throne, only to be later deposed by Phraya Kreak. Upon this successful usurpation, Phraya Kreak assumed the regnal title Sindhob Amarin.
Following his victory over the ruling house of Mueang Wat Derm, Sindhob Amarin consolidated political authority over both Mueang Wat Derm (Ayodhya) and Mueang Phreak, thereby unifying two key centers within the lower PasakâÂÂMenam corridor. Notably, despite this expansion of control, he continued to maintain his principal seat of power at Phraek Si Racha.
The legacy of Phraya Kreak (also known as Phraya Phreak (), the title which later also referred to Intharachathirat of Ayutthaya) persisted into the Ayutthaya period through regalia believed to have originated in his reign. Chief among these was the Phra Saeng Khan Chaiyasi (; ), regarded as a sacred emblem of kingship and employed in the royal oath-taking ceremony (). A late Ayutthayan account, ', states that this sword was lost during the succession conflict during the late period of King Thai Sa in the 18th century, when fleeing princes cast it into the river amid political turmoil.
Equally significant was the Crown of Phraya Kreak, which symbolized primordial royal authority and continuity of sovereignty. Unlike the sword, the crown was said to have survived the dynastic upheavals of the late Ayutthaya court and remained in royal possession until the fall of Ayutthaya in 1767.