The first pope who took the name Leo became pope in 440. Known as “Leo the Great,” the Roman aristocrat was a peacemaker who is most well-known for meeting Attila the Hun in 452 and successfully managing to dissuade him from invading Italy. He was also a doctor of the Church, promoted the doctrine of papal primacy (the authority of the pope over other bishops), and wrote 96 sermons that have been passed on to us today. A historic last (at least for now) was Pope Leo X (1513-1521). He was the last pope not to have been a priest at the time of his election to the papacy.