A person who claims or exercises the office of pope (papacy) in opposition to the true pope of the time. There have been about 35 antipopes in the history of the Catholic Church, the last being Felix V (1439–49). There have been two main causes. First, a disputed election, in which there was disagreement among the electors or other interested parties as to which person was elected pope. Secondly, the desire of various Holy Roman Emperors to have a more pliable person as pope, and their setting up of antipopes for this purpose. In some cases, especially during the Great Schism of 1378–1417, it is very difficult to say which person was the true pope and which was the antipope.