The Act of Succession of 27 March 1953 (Danish: tronfølgeloven) was adopted after a 1953 referendum in Denmark and dictates the rules governing the line of succession to the Danish throne. The 1953 referendum changed the act so that it became possible for a woman to inherit the throne in the event that she has no older or younger brothers, a system known as male-preference cognatic preference primogeniture. As the reigning King Frederick IX had three daughters and no sons, this meant that Princess Margrethe became the heir presumptive instead of her uncle Prince Knud. As Frederick IX's wife Queen Ingrid was not expected to (and in fact did not) have any more children, this effectively ensured that Princess Margrethe would become Queen of Denmark, which she did. The act also removed the suc