The First Dogmatic Constitution on the Church of Christ, approved by the Vatican Council on 18 July 1870, includes the following, language about the authority of the Pope:

On the infallible teaching authority of the Roman Pontiff

Therefore, faithfully adhering to the tradition received from the beginning of the Christian faith, to the glory of God our savior, for the exaltation of the Catholic religion and for the salvation of the Christian people, with the approval of the Sacred Council, we teach and define as a divinely revealed dogma that when the Roman Pontiff speaks EX CATHEDRA, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to.be held by the whole Church, he possesses, by the divine assistance promised to him in...