 There was no law concerning this matter, it was purely a matter of custom.In 1917, Rama VI declared a new law, the "Form of Address for Woman Act, 1917".The act mandated a new form of address, "Nangsao" (นางสาว) ('Miss') for women who were unmarried (the wording used in the act was "woman who has no husband") and "Nang" (นาง) ('Missus' [Mrs.]) for women who were married ('married woman or woman who has husband').