He only returned to Montreal after he had been granted amnesty by the colonial government as well. In 1848, he was elected member of the new united Legislative Assembly of the Province of Canada in the riding of Saint-Maurice. In severe disagreement with the emerging French Canadian Liberal Party, he became an independent Member of Parliament. A convinced republican after a long exile in the United States and France, Papineau supported the Montreal Annexation Manifesto that called for Canada to join the United States of America. Louis-Joseph Papineau, along with John Molson Jr., the son of John Molson, and Horatio Gates, served as the first Vice-Presidents of the Montreal Mechanics' Institute. He participated in the creation of the "Parti rouge". He was defeated in 1851 but elected in a by-election in 1852. He did not present himself again in the elections of 1854. He retired from public life and reappeared only once to hold a conference at the "Institut Canadien de Montréal" in December 1867. He died at his manor in Montebello, Quebec near the modern Château Montebello on September 23, 1871. Papineau's manor house in Montebello, and his house in Montreal, have both been designated as National Historic Sites of Canada. On October 21, 2012, a monument to his memory was unveiled at Saint-Denis-sur-Richelieu by Québec Premier Pauline Marois. Papineau married Julie Papineau (née Julie Bruneau) in Quebec City on April 29, 1818. Together, they had 9 children .