Mahidol Adulyadej  Mahitala Dhibesra Adulyadej Vikrom, the Prince Father ( , 1 January 1892 – 24 September 1929), formerly Mahidol Adulyadej, Prince of Songkla () or Mahidol Songkla, was the father of King Ananda Mahidol (Rama VIII) and King Bhumibol Adulyadej (Rama IX) of Thailand. He was also regarded as the father of modern medicine and public health of Thailand. He also founded the House of Mahidol or the present Royal Family of Thailand. Prince Mahidol was the 69th child of King Chulalongkorn and the 7th of Queen Savang Vadhana. His mother also adopted four other royal princes whose commoner mother (Chao Chom Manda) had died; among them was Prince Rangsit Prayulsak, later Prince of Chainat, who became a very close friend of Prince Mahidol during his childhood. Later in their lives, Prince Rangsit would play a pivotal role in Mahidol's career, and would later be appointed regent to one of Mahidol's sons, Bhumibol. Like the other sons of King Chulalongkorn, Prince Mahidol started his education at the Royal School within the Grand Palace. He received the title of Prince of Songkla at age 13. He was sent to London in 1905, and after spending a year and a half in Harrow School, he moved to Germany to join the Royal Prussian Military Preparatory College at Potsdam according to the wish of his father, then continued his military education at the Imperial Military Academy at Groß–Lichterfelde in Berlin. Following the wish of his half-brother, King Vajiravudh, he then entered the Imperial German Naval Academy at Flensburg-Mürwik. While there, he won a competition in submarine design. He was commissioned Lieutenant in both the Imperial German Navy and the Royal Thai Navy in 1912. The start of World War I compelled the Prince to come back to Thailand in 1914; he was assigned to a teaching post at the Royal Naval Academy. He continued his interest in smaller vessels, including submarines and torpedo boats; this later led to conflict at a meeting, where he was overruled by senior naval officers, most of whom were British graduates and preferred larger vessels. The Prince, feeling that his expertise would never be used, resigned his post nine months after joining the Navy.