The Decrees of the Vatican Council (Vatican I, English)

The First Vatican Council was the twentieth ecumenical council of the Roman Catholic Church, which met three hundred years after the Council of Trent. It was convened in order to refute modern theological differences and to define Catholic doctrine in response to the rise of modernism. The First Vatican Council approved two constitutions: one on the Dogmatic Constitution of the Catholic Faith, and the other—famously—on papal infallibility. The council also clarified the role of the pope in the Roman Catholic Church.