The british officially took over the french colony of Nouvelle-France in 1763. The americans occupied Montreal at one occasion (during the revolution for eight months) but came close during the war of 1812). Montreal was the commercial capital of Canada because of it's port, location and historical importance. The economical importance of Montreal started to decline after the great depression and was more noticable around the 1960's. Three more recent and important events are the World exposition in 1967 (on Ile Notre-Dame), the 1976 Olympics and the 350th anniversary of Montreal in 1992.
Some recent and important political events : the "revolution tranquille" in the 60's (where the francophone population drifted from the church and took more control), the 1976 election of the Parti Quebecois (political party dedicated to the separation of Quebec from Canada) and the 1980 referendum (a majority of the population voted against separation).