Epilogue: We've moved on. A new DM is running, and we've walked away from the old DM's adventure entirely.
That doesn't keep the old DM from trying to tell the new DM what the world looks like though.
In our games each player creates their character, and the region or city they come from, the are where they plan to use as the base for their adventures.
Unclaimed areas of the world are open for use and abuse as the DMs see fit.
The DM we walked away from is claiming that his territory is one entire continent, Africa. Egypt is pretty much gone and his Bantu empire is the greatest threat that nobody has ever heard of.
The new DM cast a brief but effective
Dispel BS on that, and is continuing with his game (currently based in Egypt) as planned.
It is decidedly un-Christian of me to take delight in someone else's discomfort. But I'm not always as good a Christian as I should be.
<Note to the Mods: More a joke than anything religious. No offense intended to anyone.)