So there's Fabian, little more than a tourist, listening in as the locals debate the merits of various believers among them as to who would make their best new leader. All of a sudden, a dove--a pigeon, likely an ancestor of those flocks of pigeons that still make their home around the Vatican--swoops out of the air and lands on Fabian's head. Knowing the symbolism of the New Testament, where the Holy Spirit "like a dove" was said to have descended upon Jesus during his baptism by John the Baptist, the crowd, seeing Fabian with this bird suddenly landing on his head, promptly on the spot hails him as the new Bishop of Rome.
So there you are: a visitor, a tourist, suddenly finds himself Pope because a bird lands on his head. Stupid Romans? A sign from God? Who can say? All I know is that Fabian ended up being a pretty good Pope, ending as a martyr himself to the rage of Decius on this day in the year 250. I like to think of him as the Patron Saint of You Never Know What's Gonna Happen.