On 23 September 1896, Victoria surpassed her grandfather George III as the longest-reigning monarch in British history. The Queen requested that any special celebrations be delayed until 1897, to coincide with her Diamond Jubilee, which was made a festival of the British Empire at the suggestion of the Colonial Secretary, Joseph Chamberlain. The prime ministers of all the self-governing Dominions were invited to London for the festivities. One reason for including the prime ministers of the Dominions and excluding foreign heads of state was to avoid having to invite Victoria's grandson, Wilhelm II of Germany, who, it was feared, might cause trouble at the event.