There is also a (bit wild) theory that St. Mark's relics in Venice are actually remains of Alexander the Great. The idea is that he was buried in Alexandria in Egypt and when the Christians started looting and pillaging someone swapped them for St.Mark's remains as those would be protected from them
I was at St.Mark's Basilica just a few days ago (I live in Venice). An informed archeologist pointed to a specific stone decoration on the north facade, telling me that it was depicting Alexander the Great, and this was confirmed only by very recent studies in Alexandria (where she was going to go back the following week).
