Holy See

Apostolic points to the connection to the apostles appointed by Jesus, following him. The origin goes back to the New Testament: "You are Peter, and on this rock I will build my church ..." Gospel of Matthew (16:18 EU). The apostolic see was initially understood to be all the episcopal sees that were in direct apostolic succession. Among them, Alexandria, Antioch, Jerusalem and Rome had a primacy as patriarchal sees. Besides Rome, only the diocese of Mainz still bears the designation Holy See.

This view was later used for the Roman episcopate. As a result, the Apostolic See became more and more associated with the succession of Peter and his successors as bishops of Rome (Sedes Apostolica Romana). In the 7th century, the term ecclesia universalis (universal church) focused more and more on the ecclesia romana (Roman church), thus limiting itself to the occidental expression. Since Pope Damasus I (366-384) the conviction developed that only the bishop of Rome could claim to sit on the Holy See of Rome. With Pope Siricius (384-399), the sole title of Pope solidified to that of Bishop of Rome. From this, with Pope Leo I the Great (440-461), the title Vicarius Christi arose in succession, placing the Holy See in Rome on an equal footing with the Roman Empire.

The diocese of Rome extends beyond the borders of the Vatican City State into Italy, and the Pope is the bishop of this Holy See.

The Holy See in the person of the Pope (identity in the sense of canon law and international law) is completely sovereign and, according to widespread international law doctrine, is regarded as an original, non-state subject of international law. In international law, this is currently the only case in which a natural person, in his official capacity by virtue of his office and for the duration of that office, is accorded subjectivity under international law that is not derived from any superior legal subject under international law (apart from the Grand Master of the Order of Malta). This distinguishes the Pope from an ordinary head of state who acts for a subject of international law but is not himself a subject of international law. The reason for this situation is that with the end of the Papal States, the Holy See was not to be left without this status, and after the recognition of the Vatican as a residual ecclesiastical state, this dual sovereignty in international law has remained.

The Holy See is not identical with the Catholic Church, which is a separate legal subject. The Catholic Church itself is not a subject of international law, but the Pope, or rather the Holy See, represents it externally as head and can thus defend its interests in diplomatic dealings.