The Grand Lodge of England assumed that title in the year 1813, because it was the n formed by the Union of the Grand Lodge of the Ancient, the “Grand Lodge of Free and Accepted Masons of England according to the Old Institutions, “and the Grand Lodge of Moderns, the “Grand Lodge of Free and Accepted Masons under the Constitution of England. “The Body thus formed, by which an end was put to the dissensions of the Craft which had existed in England for more than half a century, adopted the title, by which it has ever Since been known, of the United Grand Lodge of ancient Freemasons of England (see Union of 1813).
– Source: Mackey’s Encyclopedia of Freemasonry