Infallibility Used Only Twice

The 1950 definition holds particular significance within Catholic theology because it represents one of only two occasions since the doctrine of papal infallibility was itself formally defined at the First Vatican Council in 1870 on which a pope has exercised that authority through a solemn ex cathedra definition, the other being the 1854 definition of the Immaculate Conception, issued before infallibility was formally defined but generally treated by later Catholic theology as an instance of the same authority. Outside these two specific pronouncements, Catholic teaching holds that papal statements, even significant ones, generally do not carry this particular formal status.

The Assumption dogma is accepted within Catholic teaching but is not shared by Eastern Orthodox Christianity, which affirms a closely related belief in the Dormition through its own distinct theological and liturgical tradition rather than through submission to a formal papal definition, and is generally rejected or regarded as lacking clear scriptural basis by the great majority of Protestant traditions, for whom papal infallibility itself is not an accepted category of religious authority.

The definition remains, alongside the Immaculate Conception, one of the clearest examples in modern Catholic history of a doctrine moving from broad devotional consensus to formally binding dogma through explicit exercise of papal teaching authority.