Although the Queen is the official head of State in Canada, the Prime Minister is the real power of government. As both the head of the executive and legislative branches of government in the Canadian Parliamentary system, the Prime Minister can set the agenda and the pace at which it is pursued. He or she also serves as the public face of the political party they lead and hence becomes the defacto spokesperson of that party. The Canadian political timeline is separated by the time in office of the various people who have served as Prime Minister.