Pierre Elliott Trudeau (1919 – 2000) was a Canadian politician who served as leader of the Liberal Party of Canada from 1968 to 1984 and as the 15th prime minister of Canada (1968–1979 and 1980–1984). His political longevity and the fundamental changes he initiated in Canadian politics and society at large make him arguably the most important Canadian figure of the latter half of the 20th century.