The magisterium of the Catholic Church is the church's authority or office to give authentic interpretation of the word of God, "whether in its written form or in the form of Tradition". According to
A part of the Ghent Altarpiece showing three popes (Martin V, Gregory VII and Antipope Alexander V) and other bishops
The magisterium presiding over a council. Shown here is the First Vatican Council, c. 1870.
Saint Peter's Basilica facade, Rome, Italy
Tuam Cathedral of the Assumption Sacred Heart Detail 2009 09 14
Papal infallibility is a dogma of the Catholic Church which states that, in virtue of the promise of Jesus to Peter, the pope when he speaks ex cathedra is preserved from the possibility of error on d
Magisterium
…from this single deposit of faith." The exercise of the Catholic Church's magisterium is sometimes, but only rarely, expressed in the solemn form of an ex cathedra papal declaration, "when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, [the…
Pope Pius IX (1846–1878), during whose papacy the doctrine of papal infallibility was dogmatically defined by the First Vatican Council
1881 illustration depicting papal infallibility
The only ex cathedra application of papal infallibility since its solemn declaration has been for the Marian Dogma of Assumption in 1950. Painting of the Assumption, Rubens, 1626
Supporters of the pope outside the United Nations in 2008 with a banner quoting Matthew 16