There's a modern theory that at the time of rise of Christianity the remains of Alexander The Great were smuggled...

There's a modern theory that at the time of rise of Christianity the remains of Alexander The Great  were smuggled to Italy and were mistakenly buried there as the remains of St. Marc at the Basilica di San Marco in Venice.

Some further symbolism:
(from http://www.planetware.com/venice/basilica-of-st-mark-i-vn-vbsm.htm)
"The north facade of the Basilica of St Mark, facing the Piazzetta dei Leoncini, contains in the last arch the Porta dei Fiori, the Door of the Flowers, which merits close examination. Its relief depicts the Nativity (13th century), framed by foliage, angels and Prophets.Also worth noting are two other reliefs (towards the Piazza): the Etoimasia (seventh-eighth century) depicts the throne of the Judge with six sheep on each side (symbolizing the Twelve Apostles). The other relief shows Alexander the Great whose chariot is being drawn upwards by two griffins (10th century)."

Is it possible this actually symbolizes 13Magnus? The 12 Sheep +a 1 Judge  = 13 Great beings = 13Magnus and their guardianship of the Alexandrian artifacts.
http://www.planetware.com/venice/basilica-of-st-mark-i-vn-vbsm.htm