Catholicism
Catholics believe that papal authority (in very specific, solemn occasions called "ex Cathedra"), the Bible, and the conclusions of ecumenical councils are infallible, while most Protestants believe in an infallible Bible but not an infallible Pope. Papal infallibility has been declared twice in the history of the Catholic Church. Once to state that Mary was conceived without sin and another to state that Mary was assumed into heaven body and soul.