The work begun at the Charlottetown and Quebec City conferences of 1864 was completed at a third conference in London. Between early December 1866 and early February 1867, the Canadian delegates met with representatives of the imperial government to prepare the British North America Act, which was passed on 29 March 1867 and came into effect on 1 July 1867. The act codified the federation of the Canadas with New Brunswick and Nova Scotia. It was, declared Thomas D’Arcy McGee in the House of Commons on 14 November 1867, “the first Constitution ever given to a mixed people, in which the conscientious rights of the minority are made a subject of formal guarantee.”