Pope Leo XIII was the first pope in over 1,500 years to lack temporal authority. Leo XIII took this opportunity to refashion the papacy as a pastoral office focused on teaching. He wrote eight-seven papal encyclicals!
He is best known for his Rerum novarum (1891) that outlined the Church's doctrine of social justice. He is also remembered for Apostolicae Curae (1897), which declared Anglican orders utterly null and void.