Parti social démocratique du Québec
The Parti social démocratique du Québec was the Quebec wing of the Co-operative Commonwealth Federation. It was founded in 1939 as the Fédération du Commonwealth Coopératif and was led by Romuald-Joseph Lamoureux in the 1944 general election, by Thérèse Casgrain from 1951 to 1957 and by Michel Chartrand from 1957 to 1960. The name Parti social démocratique was adopted in 1955.
The party was refounded in 1963 as the New Democratic Party of Quebec, however the party soon split over the issue of Quebec self-determination with Quebec nationalists leaving to form, in November 1963, the Parti socialiste du Québec led by former PSD leader Michel Chartrand.
The NDPQ renamed itself the Parti de la Democratie Socialiste following a 1991 split with the federal NDP over the question of Quebec independence.