Before 1917, members of the British Royal Family had no surname, but only the name of the house or dynasty to which they belonged. Kings and princes were historically known by the names of the countries over which they and their families ruled. Kings and queens, therefore, wrote their signatures by their first names only. The names of dynasties tended to change when the line of succession was taken by a rival faction within the family or when succession passed to a different family branch through women. In 1917, King George V adopted Windsor as the name of the House or dynasty and also as the surname of his family. Queen Elizabeth II was born with the last name Windsor. However, in 1960, The Queen and The Duke of Edinburgh decided that they would like their own direct descendants to be distinguished from the rest of the Royal Family (without changing the name of the Royal House), as Windsor is the surname used by all the male and unmarried female descendants of George V. It was therefore declared in the Privy Council that The Queens descendants, other than those with the style of Royal Highness and the title of Prince/Princess, or female descendants who marry, would carry the name of Mountbatten-Windsor.