In addition to Prince George, whom helped inaugurate the London Museum?   
London Museum: The London Museum, established to illustrate the history of London, was inaugurated on 21 March 1912 by King George V with Queen Mary and Princess Mary and Prince George in temporary accommodation at Kensington Palace. Prince George, Duke of Kent: Prince George, Duke of Kent, {'1': ", '2': ", '3': ", '4': "} (George Edward Alexander Edmund; 20 December 1902 – 25 August 1942) was the fourth son of George V of the United Kingdom and Queen Mary.
King George V