 Formal surnames were a 20th century innovation of Sandhurst-educated King Vajiravudh (Rama VI, r. 1910–1925).The "Surname Act of 2013" decreed that "married woman can bear her husband's surname or keep her maiden name" (Clause 6 of the act).A woman's right to choose her surname ended in 1941 with the passage of the "Personal Name Act 1941".