I'm trying to retrieve information about how the primi of the twelve houses are chosen. Who's willing to help me out?
Bjornaer. The Primus is chosen by the Bjornaer Council, which in turn is voted by the House members democratically.
Bonisagus. The Primus appoints his successor among those magi with the appropriate requisites; the Colentes Arcanorum may replace the Primus but have never done so.
Criamon. The primus is the first to claim the title in a mystical consensus process at the Cave of Twisting Shadows.
Ex Miscellanea. The primus is elected by the house members among the current members of Cad Gadu.
Flambeau. I could find no information, but I confess not looking too carefully.
Guernicus. The Primus is chosen by the Magvillus Council, which could also replace him but never has. The Council chooses its own new members.
Jerbiton. Despite careful searching in HoH:S, I could find no information; but I do seem to recall having read somewhere that the Primus was chosen democratically by vote.
Mercere. I could find no information except for the fact that the current Prima is the daughter of the previous Primus, and her own daughter "is expected" to take her place.
Merinita. Again, I could find no information though as in the case of Flambeau I did not look too carefully.
Tremere. The Primus appoints his successor (HoH:TL), the Legatus; should both die, the Exarch of Rome is next in line. There's also a complex certamen system that allows one to challenge the Primus for leadership.
Tytalus. The Primus is he who bosses the other Tytali in recognizing him as a Primus
Verditius. By tradition, eldest living filius of the Primus becomes the new Primus. It's not clear what happens if the previous Primus had no living filii.
Ex Miscellanea: I don't have the books handy, but isn't there something about the Council of Four choosing the Primus? Cad Gadu determining the successor doesn't seem right to me.
Flambeau: Maybe the flamines have something to do with this?
Mercere: It's definitely a hereditary title (well, unless someone finds that thing that may or may not exist...). Because of Belin, the family tends to favor younger girls over older boys as heirs.
Merinita: I imagine that ever since Quendalon disappeared, the senior members of the Cult have decided who their next Primus or Prima will be, probably using some secret, mysterious and spooooooky process, likely involving cloaks. Maybe they each propose a candidate and then draw lots? There's likely a curse involved, since strange things keep happening to their picks.
Tytalus: I thought there was something about the Greens and the Purples at Fudarus fighting for the title...
One year after the last Primus dies, all T's who want to toss their hat into the ring do so, and there's a grand meeting of "contention". Apparently it's like a full-contact debate, in part using Debate rules found in HoH:Societatus and in part using any tactic or dirty trick the candidate can think of, on or off the floor, before or during the actual event. Last mage standing wins. (So it's actually much harsher than mere "bullying", altho' that could certainly be a legit part of it.)
(The "Greens & Purples" refer to sides in the current state of affairs - the prev Primus went into "permanent" Twilight, and time passed and there was a moot and a new primus properly determined, and then the prev primus woke up - so both are considered validly primi by House Guidelines. It's split the House, and has since before 1200, and that's ok by House Tytalus. Fun, fun, fun!)
The OP was right; when a primus Ex Miscellanea dies or enters Final Twilight, the current membership of Cad Gadu becomes candidates for the primus-ship. The House must reach a consensus over which candidate they support. The new primus then dismisses all members of Cad Gadu, and appoints new ones.
It is not clear whether the Council of Four are members of Cad Gadu or not; I had certainly intended this to be the case, but seem to have neglected (or cut...) a statement to that effect. We know that one member of the Council of Four is a member of Cad Gadu at least - Gwhyr of the Columbae.
Ah, that's right, now I remember. Thanks!
This leaves Jerbiton, Mercere and Merinita.
Any interesting tidbits that might lead at least to some conjectures?
For Mercere, there is some very mild evidence suggesting that it may tend to "stay within the family", but nothing conclusive at all, as far as I can tell.
For Jerbiton, generally most don't want it, and the power of the position is only based on charisma. Andru has a lot of power because the Fall of Constantinople has galvanised his Housemates to be less insular and try to act together, and he' leading and being swept along by, that change. His successor, though, he or she is likely to be a bit of a friebrand, and that'll be interesting.
