After being educated in France, Germany, and the United Kingdom, he joined the British Royal Navy in 1939, aged 18. From July 1939, he began corresponding with the thirteen-year-old Princess Elizabeth, whom he had first met in 1934. During the Second World War, he served with distinction in the Mediterranean and Pacific Fleets. Philip and Elizabeth have four children: Charles, Prince of Wales; Anne, Princess Royal; Prince Andrew, Duke of York; and Prince Edward, Earl of Wessex. Through a British Order in Council issued in 1960, descendants of the couple not bearing royal styles and titles can use the surname Mountbatten-Windsor, which has also been used by some members of the royal family who do hold titles, such as Anne, Andrew, and Edward.