Mom Chao

Thai royal and noble titles are the royal and noble styles indicating relationship to the king which were introduced by King Trailokanat (reigned 1448–1488). The system is rooted in the Thai language equivalent of feudalism, Sakdina (: "power over fields"). It is somewhat similar to peerage, but more complicated and obscure even to most Thais. A title of honor may not be confined to the beginning or the end of the name, but may be split across the name. Those with titles ceased to be known by personal names, and were referred to by the awarded (or similar) title. The King may bestow any title on anyone, although such promotion is personal and the person's children will not normally benefit from it.

There are two styles which can be used for a king in ordinary speech, depending on whether he has been crowned:

Traditionally, titles of royal wives depended on their birth titles and royal favour; only princesses of high birth (Chao Fa, Phra Ong Chao and Mom Chao Ying) assuming titles higher than Chao Chom. There were no clear rules about the hierarchy of titles above Chao Chom until the time of King Mongkut, and titles changed over successive reigns. The rule about commoners also seems to be evolving, and it appears that there are no more restrictions on a commoner from becoming queen. Most of the titles below are from King Vajiravudh's 1924 enactment of the Succession Law.

Holders of these titles are still considered royal, since they are (at most) two generations removed from a king. Nai Luang (ในหลวง) is an epithet for a king. Children of a king are called Luk Luang ( "royal children"), and grandchildren of a king are called Laan Luang ( หลวง "royal grandchildren"). In English, they are normally called "prince" or "princess". Special forms are used when one wishes to address them, although the language is less elaborate than when speaking to the king or the queen. A male Luk Luang who does not accede to the throne would assume a new royal surname, normally reflecting his birth name (as opposed to an honorific given later). The surname can be used by his wife if she is a commoner by birth, possibly with Na Ayudhya added if she has no noble title. It is otherwise not normally used until his children (or grandchildren) first hold the title of Mom Chao, when the surname will first appear in their names.

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