The Catholic Church holds that Jesus Christ founded one Church on the Apostle Peter, whose episcopal succession continues in the Bishop of Rome (the Pope). The Pope exercises supreme, full, immediate, and universal jurisdiction over the entire Church in matters of faith, morals, and governance. When speaking ex cathedra (from the chair) on matters of faith and morals to be held by the whole Church, the Pope is infallible—a dogma defined at Vatican I (1870). This supreme authority is exercised in collegial communion with the worldwide college of bishops.

The Magisterium—the Church's teaching authority exercised by the Pope and bishops in communion with him—is the authoritative interpreter of both Scripture and Sacred Tradition. Its teachings are categorized by binding force: defined dogmas (requiring assent of faith), definitive teachings (requiring firm assent), and ordinary Magisterium (requiring religious obedience of intellect and will). Vatican II's Lumen Gentium presents the Church as the 'People of God' and the Mystical Body of Christ, with the hierarchy serving the faithful.