It wasn’t easy for St. Mark to become the patron saint of Venice.
For around eight centuries he was just lying peacefully (well, not so peacefully since he was martyred, but at least that was over) in his tomb in Alexandria, when suddenly some businessmen from Venice decided to abduct him. So they dug him up (or whatever one does with a body in a tomb), put him in a basket covered with herbs and some pig’s flesh (to keep the pork-forbidden Egyptian Muslims off the scent, as it were), and set sail for Venice. A great storm blew up, whereupon poor Mark got himself out from under that pig and told them to lower the sails.
A miracle; and now he’s supposedly there in his Venetian Basilica, where a mosaic at the entrance tells the whole story.
All that, and he’s also the patron saint of notaries!