Following up on Ray's comments to the last post - I have found an English version of the story he references online.
"During the schism which burst between the Copts and the Melkites, the first kept the head while the body remained with the latter. On 644 A.D., a soldier sneaked into the church where the head was buried. He took it away to his ship under the impression that it was a treasure. Later, when Amro-Ebn-El-Aas (leader of the Arab troops) ordered the ships to sail off Alexandria, that particular ship could not move. Eventually the soldier had to confess and Amro handed it back toPope Benjamin. The saint''s body did not remain in Egypt, for it was stolen and taken to Venice by some Italian merchants. They built a huge cathedral in St. Mark''s name, believing that St. mark was their patron Saint. In 1968, part of his relics which is now kept in the new Cathedral in Cairo, was offered to the Egyptian Pope Cyril (Kyrillos VI) from Pope Paul VI)."
Oh, my. Imagine that you've spent 2 years writing a book about a body being taken from one place, and then be told that it was never there at all! Well, there are a few ways out of this. First, not every source says that the body was with the Melkites. Second, authors use composites all the time. Whether this story of the Melkites having the body is true or not, I think I need to composite the two churches of Egypt into one, and have the action take place there. Perhaps I can include an authors' note explaining this, and my reasons for it.
As an aside, there are those who beleive that the Venetians did not get Saint Mark's body at all: that instead, they took Alexander the Great, who was secretly buried in Alexandria. Does it matter exactly which body they took? For my purposes, no. All that matters is that the Venetians thought they had Mark, and so did everyone else.
The edits are coming along nicely!