Much work was involved in reorganising the Craft after the Union of the two Grand Lodges was achieved on 27 December 1813, so that it was not until 1817 that HRH The Duke of Sussex was able to turn to the Royal Arch. On 18 March 1817, the Royal Arch members of both of the former Grand Lodges were summonsed to a meeting at Freemasons' Hall. The Excellent Grand and Royal Chapter were opened in one room, and the Royal Arch members of the former Antients Grand Lodge opened a Chapter in a second room.
Both groups then processed into the Grand Hall where they were greeted by the Duke of Sussex who formed them into the United Grand Chapter, addressed them on the Royal Arch, appointed Grand Officers and a Committee to provide Regulations to govern the Order.
To placate the former Antients Grand Lodge members the meeting was referred to, and announced to the United Grand Lodge, as a Union, but that was a pious fiction. There had been no separate Antients Grand Chapter, the Antients Grand Lodge and its Committees had ceased to exist on 27 December 1813 and the "new" body was simply a continuation of the original 1766 Grand Chapter with the addition of those members of the former Antients Grand Lodge who were Royal Arch Masons. The fiction was continued by styling the body the United Grand Chapter of England, but that title was quietly changed to Supreme Grand Chapter in 1821.