Pastor aeternus

Pastor aeternus is the Dogmatic Constitution on the Church of Christ, issued by the First Vatican Council, July 18, 1870. The document defines four doctrines of the Catholic faith: the apostolic primacy conferred on Peter, the perpetuity of the Petrine Primacy in the Roman pontiffs, the meaning and power of the papal primacy, and Papal infallibility – infallible teaching authority (magisterium) of the Pope.

The Primacy of Simon Peter is closely related to, and indeed essential to, the papal primacy, that is, the idea that the papacy, by divine institution, enjoys delegated authority from Jesus over the entire Church. However, this doctrine of the Catholic Church makes a distinction between the personal prestige of Peter and the supremacy of the office of pope, which Catholics believe Jesus instituted in the person of Peter.

Papal primacy, the primacy of the Bishop of Rome over the whole Catholic Church, is derived from the pope's status as successor to Peter as "Prince of the Apostles" and as "Vicar of Christ" (Vicarius Christi). The First Vatican Council defined papal primacy as an essential institution of the Church that can never be relinquished.

In the primacy of the Bishop of Rome, there is a distinction between ex cathedra (magisterium infallibile et solemne) and ex sede (magisterium ordinarium) based on the munus petrinum veri in terris Vicarii Christi. The Successor of Peter has in the Universal Church a doctrinal gift ("munus doctrinae") and a teaching gift ("officium praedicationis") in faith and morality (in fide et moribus) for the special charisma (peculiare charisma Petri ) of the "Prince of the Apostles" (Princeps Apostolorum). The Successor of Peter, for his singular and communional gift of primacy ("singulare et communionale munus primatialis") has an apostolic power ("potestas apostolica") and an episcopal power ("potestas episcopalis"). Only the Bishop of Rome is in the Universal Church Primas and Apostolicus. The Church of Rome, in fact, is theological place (locus theologicus) of doctrine (ex cathedra) and teaching (ex sede) of the Universal Church ("cathedra et sedes universalis Ecclesiae"). The gift of the Roman Pontiff is expressed in his title of Magister and Doctor. Only the Church of Rome is the "Mother" () and "Teacher" (Magistra) of all churches. This is the reason because the First and Apostolic See of the Church of Rome is Nutrix ac Doctrix. The See of Rome is "Genitrix spiritualis".

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