William Lyon Mackenzie King, Pierre Trudeau and Brian Mulroney are the names of some of Canada's prime ministers. All of these prime ministers served multiple terms and oversaw some significant events in Canadian history.
William Lyon Mackenzie King served as prime minister representing the Liberal Party on two different occasions between 1926 and 1948. He helped in the establishment of old age pensions and lost his office at the start of the Great Depression. When he returned to office in 1935, he remained for 13 years with such notable accomplishments as the creation of the Canadian Broadcast Corporation, leading the country during World War II and overseeing the country's entrance into the United Nations.
Pierre Trudeau was a very popular prime minister, serving for over 14 years. He was prime minister during the time when Canada was threatened with secession from French-speaking Quebec, including the October Crisis of 1970. The Liberal Party prime minister established relations with communist China, created Petro-Canada, guided the country into the G7 and helped pass the Canadian Health Act.
When Brian Mulroney was elected as prime minister from the Progressive Conservative Party in 1984, he became the first elected conservative in 26 years. He was elected based on promises to reduce the national debt that had been growing from the spending of his liberal predecessors. But his first term was marred by scandals and poor financial management. He oversaw Canada's participation in the first Gulf War, and he passed the Environmental Protection Act and the North American Free Trade Act during his second term.