泰國王權的概念，已經演變了800多年，並形成絕對的統治權力。第一位治理統一泰國的君主，是1238年素可泰王國的開國國王室利·膺沙羅鐵  。早期泰國王權的思想是基於印度教與上座部佛教信仰所衍生出來的概念。印度教的概念是基於剎帝利（泰語：กษัตริย์）的吠陀─印度教種姓制度，或稱為武士統治者，王權是由軍事力量衍生而來。上座部佛教的概念則來自於「法王」（泰語：ธรรมราชา），而佛教是在約6世紀時引入泰國。法王的概念代表君主必須以「法」與佛陀的教導統治人民。
當1279年蘭甘亨大帝登基為王時，原始的概念被短暫替換。他背離了傳統並創造出「父權統治」（泰語：พ่อปกครองลูก）的概念取而代之，意思是君主統治人民，就好比父親教導小孩一樣。而蘭甘亨將他的名字冠以「Pho Khun」的頭銜（泰語：พ่อขุนรามคำแหง），用以加強他所創造的概念，然而其維持時間非常短暫。在素可泰王國的末期，原始的兩個宗教概念回歸，並將君主頭銜從「Pho Khun」改為「Phaya Khun」。
- The Secretariate of the House of Representatives. Constitution of the Kingdom of Thailand B.E 2550 (PDF). The Secretariat of the House of Representatives. Nov 2007 [7 November 2012]. （原始内容 (PDF)存档于2012年8月31日）.
- Cœdès, G. The Origins of the Sukhodaya Dynasty (PDF). Journal of the Siam Society (Siam Heritage Trust). 1921,. JSS Vol. 14.1b (digital): image 1 [17 March 2013].
The dynasty which reigned during a part of the XIIIth. and the first half of the XlVth. centuries at Sukhodaya and at Sajjanlaya, on the upper Menam Yom, is the first historical Siamese dynasty. It has a double claim to this title, both because its cradle was precisely in the country designated by foreigners as "Siam" (Khmer: Syain; Chinese : Sien, etc.), and because it is this dynasty which, by freeing the Thai principalities from the Cambodian yoke and by gradually extending its conquests as far as the Malay Peninsula, paved the way for the formation of the Kingdom of Siam properly so called.
- Background to a Modern Kingship. Thai Modern Monarchy. 1998. （原始内容存档于2009-11-02）.
- Prince Dhani Nivat, Kromamun Bidyadabh. The Old Siamese conception of the Monarchy (PDF). Journal of the Siam Society (Siamese Heritage Trust). 1947,. JSS Vol. 36.2b (digital): image 10 page 93 [7 March 2013].
Patriarchal Sukhothai Kingship ...The monarch was of course the people's leader in battle; but he was also in peace-time their father whose advice was sought and expected in all matters and whose judgment was accepted by all. He was moreover accessible to his people, for we are told by an old inscription that, in front of the royal palace of Sukhothai there used to be a gong hung up for people to go and beat upon whenever they wanted personal help and redress. The custom survived with slight modifications all through the centuries down to the change of regime in 1932....
- Terwiel, Barend Jan. Ahom and the Study of Early Thai Society (PDF). Journal of the Siam Society (Siamese Heritage Trust). 1983,. JSS Vol. 71.0 (PDF): image 4 [7 March 2013].
In older usage, khun was used for a ruler of a fortified town and its surrounding villages, together called a mueang; with the prefix pho (พ่อ "father") appears as Pho Khun.