What is a cathedra?
The cathedra is the chair of the bishop. The diocesan church of bishop or an archbishop is called a cathedral because it houses his episcopal chair (cathedra).
Additionally, following the First Vatican Council (1869-1870) the phrase ex cathedra, meaning "from the chair," came to signify the highest level of papal teaching. Theologians have since emphasized that a papal teaching cannot be ex cathedra unless it is 1. universal 2. supreme 3. definitive and 4. mandatory. Requiring these four qualifications before a papal teaching can be considered ex cathedra has made this type of teaching infrequent.
