Pope Leo I, also known as Leo the Great, navigated the Church through a tumultuous era marked by the disintegration of the Western Roman Empire and profound theological controversies. Known for his theological brilliance and pastoral care, he defended the Church against heresies such as Pelagianism, Manichaeism, and Monophysitism. His actions, including meeting Attila the Hun to prevent the sacking of Rome, highlight his role as both a spiritual leader and a peacemaker.