 Just months into his reign , Edward forced a constitutional crisis by insisting on marrying the American divorcée Wallis Simpson . Although legally Edward could have married Simpson , as King he was also head of the Church of England , which at that time did not allow divorced people to remarry . Edward 's ministers believed that the people would never accept Simpson as Queen and advised against the marriage . As a constitutional monarch , Edward was obliged to accept ministerial advice . Rather than abandon his plans to marry Simpson , he chose to abdicate in favour of Albert , who reluctantly became King in his place on 11 December 1936 under the regnal name of George VI . George VI and Elizabeth were crowned King and Queen of Great Britain , Ireland and the British Dominions , and Emperor and Empress of India on 12 May 1937 , the date already nominated for the coronation of Edward VIII . Elizabeth 's crown was made of platinum and was set with the Koh @-@ i @-@ Noor diamond . 
