Her Royal Highness Princess Galyani Vadhana, Princess of Naradhiwas, wrote in the preface to the book “Chao Nai Lek Lek: Yuwakasat” (1987: Preface), referring to the origin of the Mahidol royal lineage as follows: “The Mahidol Royal Lineage.”

Before the reign of King Vajiravudh (Rama VI), Thai people did not use surnames. When individuals had the same name, it was necessary to specify who their parents were or where they came from. The Surname Act was enacted in 1913 (B.E. 2456). For members of the royal family, this posed little difficulty since their names were long and unique. However, for women who married into the royal family and had no surname to identify their royal lineage, titles were used instead: Mom for commoners, Mom Luang or Mom Rajawongse for those of noble birth, Chaya for daughters of Mom Chao (His Serene Highness), and Phra Chaya for daughters of Phra Ong Chao (His Highness), followed by the name of the royal husband. For instance, after my mother received the ceremonial water blessing, she was titled Mom Sangwan in Prince Mahidol Adulyadej, Prince of Songkla, since she had not yet been granted a royal surname. In English, ‘Mom’ was not translated as ‘Princess’ but rather written as ‘Madame’, such as Madame de Pitsanulok (Mom Catherine, wife of Prince of Phitsanulok) or Madame de Songkla (my mother). While residing in the United States, Prince Mahidol used the name Mr. Mahidol Songkla, and my mother used Mrs. Songkla. All of us children, therefore, used the surname Songkla.