Philip was born into the Greek Royal Family which was exiled when he was a small boy. Formally, he was a member of the House of Schleswig-Holstein-Sonderburg-Glücksburg.
The most stable figure in his life was his uncle, Lord Mountbatten, who arranged for him to join the Royal Navy in 1939 when Philip was eighteen. Upon his engagement to then Princess Elizabeth, he renounced his Royal titles from the Greek and Danish Royal families and his Greek citizenship. After his marriage to Princess Elizabeth in 1947, her father, George VI, bestowed the title HRH (His Royal Highness) elevating Philip into the English Royal Family.
[Image courtesy of the National Portrait Gallery, London.]