Question:
Answer:
This is an interesting question. Usually one would say that the last time was on November 1, 1950, when Pope Pius XII solemnly defined the dogma of the Assumption of Our Lady into heaven. And this would really be a doctrine taught ex cathedra as contained in the deposit of faith.
Even so, the requirements for ex cathedra or extraordinary exercise of the Magisterium and the requirements for infallible teaching are not exactly the same. There can be teachings that are taught infallibly but are not presented in an extraordinary form of definition. The chief example of this would be St. John Paul II’s declaration on the ordination of women to the priesthood Ordinatio Sacerdotalis on May 22, 1994:
Wherefore, in order that all doubt may be removed regarding a matter of great importance, a matter which pertains to the Church’s divine constitution itself, in virtue of my ministry of confirming the brethren (cf. Luke 22:32) I declare that the Church has no authority whatsoever to confer priestly ordination on women and that this judgment is to be definitively held by all the Church’s faithful.
It is clear that here the pope is using his full authority and intends for his declaration to be definitive. He thus fulfills all the requirements for a dogmatic definition, even though his instruction was not announced as such. I have the personal witness of the Dominican father at the Angelicum in Rome who drew up the document that this was St. John Paul’s intention.