Mahitala Dhibesra Adulyadej Vikrom, the Prince Father, formerly Prince Mahidol Adulyadej, Prince of Songkla or Mahidol Songkla, was the father of King Ananda Mahidol and King Bhumibol Adulyadej of Thailand, and the paternal grandfather of King Vajiralongkorn. He was also regarded as the father of modern medicine and public health in Thailand. He also founded the House of Mahidol or the present Royal Family of Thailand. His two sons reigned for more than eight decades, longer than the Ibn Saud siblings of Saudi Arabia, and the Nahyan siblings of Abu Dhabi.

Ananda Mahidol was the eighth king of Siam from the Chakri dynasty, titled Rama VIII. At the time he was recognised as king by the National Assembly in March 1935, he was a nine-year-old boy living in Switzerland. He returned to Thailand in December 1945, but six months later, in June 1946, he was found shot dead in his bed. Although at first thought to have been an accident, his death was ruled a murder by medical examiners, and three royal aides were later executed following very irregular trials. The mysterious circumstances surrounding his death have been the subject of much controversy.