The modern order of succession of Thai monarchs begins with king Si Inthrathit who established the Sukhothai Kingdom in 1238, which is considered to be the first contemporary Tai-ethnic kingdom; it was ruled by Phra Ruang dynasty. Composing of 8 dynasties: Phra Ruang, Uthong, Suphannaphum, Sukhothai, Prasat Thong, Ban Phlu Luang, Thonburi, and Chakri. With brief interruptions, 55 monarchs and 27 viceroys have ruled over four successive kingdoms, the current monarch being Vajiralongkorn (Rama X) of the Chakri dynasty.
The modern perception is that there has been four distinct eras of Thai history, namely: Sukhothai, Ayutthaya, Thonburi, and Rattanakosin. However, the compilations of historical narratives from the old capital (pongsawadan krung kao) and the historical narratives from the king in the temple compiled by Prince Tisavarakumara, the Prince Damrong Rajanubhab, along with the Chronicles of Northern Kingdom's Histories included the Pre-Sukhothai and Pre-Ayutthaya monarchs as well. This means that the Sukhothai-Si Satchanalai city-states and the Siam Confederation and their monarchs is a part of the historical canon as well.
Prior to the establishment of Sukhothai, Siam was a group of petty kingdoms shifting zones of influences and mandalas through wars and political marriages. Because of this, there are kingdoms and polities which existence may overlap, hence the monarchs' reigns will also overlap or even reign two polities at once. An example are Sukhothai and Ayutthaya. Ayutthaya, in the modern sense, was established during the reign of Maha Thammaracha I of Sukhothai in 1351 in which king Uthong V & Ramathibodi I (same person with two regnal names) inherited all of the confederation's polities – uniting them, hence the reign of Ayutthaya's monarchs overlaps with 4 monarchs of Sukhothai. An example for a monarch reigning multiple polities is when king Phanom Thale Sri who reigned both the Siam Confederation and the Sukhothai-Si Satchanai city-states (together 5 different polities) at the same time in 1155, while these polities were run separately and equal to one another unlike the vassalage system in which a state is subservient to another.
The traditional accounts of the list starts with king Phra Pathomsuriya Thephanarathai Suwannabophit as the first king of all of Siam in 757 CE. He was the first king to unite petty kingdoms under one monarch. His descendants are of the Guruwamsa/Pathomsuriyawong dynasty, which is also the ancestors to most of the reigning dynasty of Sukhothai and Ayutthaya. In which, according to the traditional accounts, king Uthong V, the first king of Ayutthaya is canonically considered to be the 27th monarch of Siam. The number of monarchs up to today would total to 101 monarchs.
Regarding succession
Historical precedent Royal succession in Siam historically did not follow a single inflexible rule comparable to later European hereditary primogeniture. During the Ayutthaya period and the early Rattanakosin period, succession could pass to a son of the monarch, an in-law, a brother, another close male relative, or a prince who had previously been elevated to a senior political and military position.
Traditional palace law provided principles concerning eligibility and royal rank, but did not produce an entirely automatic line of succession. Political support among senior princes, ministers, military leaders and court officials could therefore play an important role. The absence of a universally binding order contributed to a number of disputed or violent successions during the Ayutthaya period.
An important institution was the Front Palace (วังหน้า, Wang Na), whose holder functioned as a vice-king or uparaja and was generally regarded as one of the principal potential successors to the reigning monarch. The holder could be a son, brother or other senior relative of the king, and possession of the office did not itself guarantee eventual succession.
Modern precedent Modern applications of Thai succession law demonstrate the interaction between the Palace Law on Succession of 1924 and the constitutional procedures introduced after the end of absolute monarchy in 1932. Although the legal framework has changed over time, several twentieth- and twenty-first-century accessions provide precedents for how succession has operated in practice. The precedent is hereditary monarchy with royal designation superimposed on a male-preference dynastic default, plus a constitutional mechanism for female succession
Under the conditions of an appointed heir +No.Event-An heir is appointed1The throne becomes vacant2The cabinet notifies the Parliament3The Parliament acknowledge the heir4The Parliament invites the heir to ascend the throne5The heir is crowned
Accession of Rama VIII, 1935 King Prajadhipok had not appointed an Heir to the Throne and, in his instrument of abdication of 2 March 1935, expressly relinquished his prerogative to designate a successor under Section 5 of the Palace Law on Succession of 1924. The succession therefore had to be determined according to the statutory order of succession, together with the requirement under Section 9 of the 1932 Constitution that the choice receive the approval of the House of Representatives.
The Council of Ministers examined the surviving male branches of the Chakri dynasty. Two sons of Rama VII's full brothers, Prince Chula Chakrabongse and Prince Varananda Dhavaj, were passed over: Chula because the government interpreted the succession law as excluding him on account of his foreign-born mother, and Varananda because of the status of his mother and his father's marriage. Prince Paribatra Sukhumbandhu, Rama VII's surviving elder half-brother, and his sons were likewise not considered by the Cabinet, as Prince Paribatra had been living in exile following the 1932 revolution.
The remaining principal branches considered were those descended from Prince Mahidol Adulyadej, Prince of Songkla, and Prince Yugala Dighambara, Prince of Lopburi. The government preferred the Mahidol branch, in part because Prince Mahidol's mother, Queen Savang Vadhana, held a higher royal rank than Prince Yugala's mother. Within the Mahidol branch, Prince Ananda Mahidol was senior to his younger brother, Prince Bhumibol Adulyadej. The Council of Ministers therefore resolved to propose Prince Ananda Mahidol as successor.
On 7 March 1935, the House of Representatives formally approved Prince Ananda Mahidol's accession. The Council of Ministers subsequently invited him by telegram to ascend the throne, with his reign deemed to have commenced retroactively from the moment Rama VII's abdication became effective on 2 March 1935. The official proclamation expressly described Ananda Mahidol as the first royal person in the order of succession under Section 9 of the Palace Law.
The accession of Rama VIII therefore provides an important modern example of succession in the absence of an appointed heir. Unlike the accession of Rama X in 2016, in which the legislature merely acknowledged an appointment already made by the preceding King, the 1935 succession required the government to determine the applicable dynastic order under the Palace Law and obtain the approval of the House of Representatives before inviting the successor to ascend the throne.
Under the conditions of no appointed heir No.Event-No heir is appointed1The throne becomes vacant2The Privy Council, following the Palace law and the Constitution proposes successor3The cabinet notifies the Parliament4The Parliament acknowledge the apointee or rejects the selected apointee -The throne is vacant while the parliament is debating on the apointee The cabinet is now in effect Regent pro tempore5The Parliament invites the heir to ascend the throne, if acknowledged6The heir is crowned
Accession of Rama X, 2016 King Bhumibol had formally appointed his son Prince Vajiralongkorn Crown Prince and heir to the throne on 28 December 1972.
Consequently, when King Bhumibol died on 13 October 2016, the designated-heir procedure applied rather than the procedure for selecting a successor in the absence of an heir.
The National Legislative Assembly, then acting as the National Assembly, formally acknowledged the existing appointment on 29 November 2016. Its president subsequently invited Crown Prince Vajiralongkorn to ascend the throne, and he accepted the invitation on 1 December 2016. His reign was declared to have commenced from 13 October 2016.
The accession is the most recent practical example of the distinction between parliamentary acknowledgement of an already appointed heir and parliamentary approval of a successor where no heir has been appointed.
Titles and naming conventions
Sukhothai Kingdom All of the mentioned titles are now defunct due to the abolition of the peerage
Khun — ขุน — Originally meaning “lord” or “chieftain,” Khun was a title used for local rulers or leaders of settlements. In later periods, is given to bureaucratic positions within government mostly to ministers, though a number of Shan states still retain this title for their rulers and kings. Originally a Tai word.
Khun Ban Muang - King of Sukhothai Hkun Hseng Awng Tun - King of Hsenwi Khun Khreua - King of LannaPhaya — พญา (sometimes written พระยา in later periods) — Originally meaning “lord.” In later periods, this title is given to people governing second-tier or lower-class cities. This title is now an equivalent to the title Marquess. Originally a Pali-Sanskrit word. This title was also used in numerous other Tai-ethnic kingdoms in the regions. The title is also adapted to a couple of higher titles such as Chao Phaya and Somdet Chao Phaya. Which is equivalent to Duke and Grand Duke in that order, though these title holders often do not hold fief / territory. Though when they do hold hand, it is tantamount to half the nation, such as the position of the prime minister of northern Siam, comes with the position of grand duke. The title is defunct. This title is also bestowed upon vassal kings and monarchs.
Phaya Loe Thai - King of Sukhothai Phaya Mangrai - King of Lanna Phraya Kakawannathiparatcha Wachiraprakarn - Princely monarch of Chiang Mai Phaya Khun Fong - monarch of Nan (a mixture of the title Phaya and Khun)Pho Khun — พ่อขุน — Originally meaning “lord father", is a term used for related or deceased rulers. The title is now defunct. Originally a Tai word.
Pho Khun Ram Khamhaeng - King of SukhothaiPu Khun — ปู่ขุน — Originally meaning “lord grandfather.” It is a term to used for deceased rulers. The title is now defunct. Originally a Tai word.Pu Phaya — ปู่พญา — Originally meaning “lord grandfather.” It is a term to used for deceased rulers. The title is now defunct. Originally a Tai + Pali-Sanskrit word.Phrabat Kamrateng An Sri — พระบาทกัมรเตงอัญศรี — The monarch also adopted the Khmer prestige title Kamrateng An (Thai: กมฺรเตงฺ อญฺ), meaning "our lord", as regnal title. The title is now defunct. Originally a Khmer word.
Kamrateng An Sri Inthrabodinthrathit - King of Sukhothai
Ayutthaya and later kingdoms All of the mentioned titles are now defunct due to the abolishment of the peerage, except the title of Phra Chao and onwardsMuen — หมื่น — Originally meaning "officer/baron." It is a title typically bestowed upon vassal king or a regional monarch and is not normally used on the kings of the Chao Phraya basin. The title is now defunct. In the chao phraya basin, it is bestowed upon officers within the central government.
Muen Soi Chiang Khong - Princely monarch of NanThao — ท้าว — Originally meaning "lord/lady/sir/dame." It is a title typically bestowed upon a vassal king or a regional monarch and is not normally used on the kings of the Chao Phraya basin. The title is now defunct. In the chao phraya basin, it is bestowed upon officers within the central government and/or people who have achieved a great feat, akin to a knight or dame.