Origin and history
During the canonization process employed by the Roman Catholic Church, the Promoter of the Faith (Latin: promotor fidei), popularly known as the Devil's advocate (Latin: advocatus diaboli), was a canon lawyer appointed by Church authorities to argue against the canonization of a candidate. It was this person’s job to take a skeptical view of the candidate's character, to look for holes in the evidence, to argue that any miracles attributed to the candidate were fraudulent, and so on. The Devil's advocate opposed God's advocate (Latin: advocatus Dei; also known as the Promoter of the Cause), whose task was to make the argument in favor of canonization. During the investigation of a cause, this task is now performed by the Promoter of Justice (promotor iustitiae), who is in charge of examining the accuracy of the inquiry on the saintliness of the candidate. The Promoter of the Faith remains a figure in the Congregation of the Causes of Saints and is also known as the Prelate Theologian.
The office was established in 1587 during the reign of Pope Sixtus V. The first formal mention of such an officer is found in the canonization of St Lawrence Justinian under Pope Leo X (1513-1521). Pope John Paul II reduced the power and changed the role of the office in 1983. In cases of controversy the Vatican may still seek to informally solicit the testimony of critics of a candidate for canonization. One notable example of this was in 2003, when author Christopher Hitchens, an atheist and outspoken critic of Mother Teresa, was asked to testify during her beatification hearings. The number of canonisations increased, from 330 between 1588 and 1978, to 483 under John Paul II's pontificate (1978-2005, an average of 18 canonisations per year).