Prince Philip, Duke of Edinburgh, Earl of Merioneth and Baron Greenwich, was born Prince of Greece and Denmark in Corfu on 10 June 1921; the only son of Prince Andrew of Greece. His paternal family is of Danish descent - Prince Andrew was the grandson of King Christian IX of Denmark. His mother was Princess Alice of Battenberg, the eldest child of Prince Louis of Battenberg and sister of Earl Mountbatten of Burma. Prince Louis became a naturalised British subject in 1868, joined the Royal Navy and rose to become an Admiral of the Fleet and First Sea Lord in 1914. During the First World War he changed the family name to Mountbatten and was created Marquess of Milford Haven. Prince Philip adopted the family name of Mountbatten when he became a naturalised British subject and renounced his Royal title in 1947. Prince Louis married one of Queen Victoria's granddaughters. Thus, The Queen and Prince Philip both have Queen Victoria as a great-great-grandmother. They are also related through his father's side. His paternal grandfather, King George I of Greece, was Queen Alexandra's brother.