Many of the alleged prophecies were written after the events “predicted” Other prophecies are vague, and open to multiple interpretations.
It is said that before the conclave that elected Pope John XIII, Cardinal Spellman of New York hired a boat, and flock of sheep, and was on board while it cruised up and down the Tiber River. The prediction for the election of Pope John XIII, was Pastor et Nauta, (Shepherd and Sailor). Pope John XIII never was a sailor, but since he was Cardinal Archbishop of Venice (a former seafaring city) it was said that he fulfilled the prophecies.
Another problem is that the alleged prophecies do not predict how many Popes will reign before the final pope, (Petrus Romanus).