Ananda Mahidol
In 1935 when King Prajadhipok abdicated without designating an heir, the cabinet took five days to consider possible successors within the Royal House of Chakri bloodline before setting upon Prince Ananda Mahidol, the eldest heir of Prince Mahidol Adulyadej. This choice followed the 1924 Law of Succession and was also approved by the National Assembly. No debate was needed when the unmarried young King Ananda Mahidol died unexpectedly on 9 June 1946. His younger brother, Prince Bhumibol Adulyadej, was undisputed heir and succeeded to the throne, reigning until his death on 13 October 2016.