Thanks Yaz, that's interesting and would seem to narrow the choices. What places make sense that might reasonably be considered semi-autonomous baronies at the start of the Mage Wars? Maus and Starport seem off the table.

Glendour is close, but too close and probably too small at this time to be semi-autonoumous.

Maybe Bramwald, although I also wonder if Bramwald is really semi-autonomous at this time?

or Maybe Boggy Bottom or Pim or Loch Gloomen - the Dismal swamp (Great Swamp of Mil) area could easily be semi-autonomous and it is close to the Ash hills so that might have been all part of the same territory. It would also explain why Raddan needed more land. There is only so much land in the swamp. The drawback is Raddan would have to march through Vestfold and Booh to get to Blackmoor Castle, but that's maybe not such a big deal.

Another point in favor of Raddan's semi autonomous barony being the Dismal swam area is that we have him in control of it later. So if he starts with the swamp and then conquerors Blackmoor we end up with all four factions in place.

What do you all think?

Maybe the whole Blackmoor is the semi-autonomous barony mentioned. At the time, after all, Blackmoor is still a (far away) barony of the Thonian empire and not yet an independent kingdom.