Papal infallibility, in Roman Catholic theology, the doctrine that the pope, acting as supreme teacher and under certain conditions, cannot err when he teaches in matters of faith or morals.

When was papal infallibility last used?

In the 103 years since Vatican I, this authority has been used only once, in 1950, when Pope Pius XII solemnly defined The new dogma of the Virgin Mary's bodily assumption to Heaven.

Is the Catholic Church infallible?

Catholic Church. Catholicism teaches that Jesus Christ, "the Word made Flesh" (John 1:14), is the source of divine revelation and, as the Truth, he is infallible. ... Catholic theology divides the functions of the teaching office into two categories: the infallible sacred magisterium and the fallible ordinary magisterium.