Of all the men who have become pope, those named Leo have occupied that office 14 times. Of those 14, four stand out either for good or for dubious reasons. The four are Leo I or the Great, Leo X, Leo XIII, and now Leo XIV. Except for Leo XIV who has yet to prove himself, each left a mark that reflected his time.
Probably the greatest of them all was Leo I or the Great (440 to 461), due to several achievements even as the Roman empire disintegrated. He established the Petrine Doctrine on the supremacy of Rome over such other big bishoprics as Constantinople and Alexandria. He was, Pope Benedict XVI, remarked in 2008, "truly one of the greatest pontiffs to have honoured the Roman See and made a very important contribution to strengthening its authority and prestige." Besides taking the initiative to assert Rome's predominance over European Christianity, Leo, in 452, successfully pleaded with Attila the Hun not to destroy what remained of the Roman Empire.