Apostolic succession
The Latin and Eastern Catholic Churches consider the pope (bishop of Rome) to be the single Vicar of Christ, successor of Saint Peter, and leader of all their bishops (Patriarchs included), in Apostolic succession to the apostles. As such, the Catholic Church does not see the pope merely as being "first among equals", but as actually holding an office with supreme authority in canon law over all other bishops. This jurisdictional claim was one of the main causes of the East-West Schism in the Church, which became formal in 1054.