That is not too far from canon.
"865 Sixth Grand Tribunal of the Or-
der of Hermes. The boundaries
of the Tribunals are formally set
according to the break-up of the
Frankish Empire, and they are
also named as the Rhine, West
Franks, Lotharingian, Britannian,
Roman, Theban, Eastern, and
Greater Alps Tribunals."
(The Lion and the Lily p141)
Note also that Britanny was part of the Britannian tribunal at this time.
They never do describe though how they get from there to the canon tribunals of 1220 though...
Note, that the organizational history of the Order of Hermes is distributed over many books, and hence requires judicious reading at the very least.
We have GotF p.140:
773 Second Grand Tribunal of the Order of Hermes. Procedures for lesser Tribunals are established: a Tribunal shall consist of at least twelve magi from at least four covenants.
This delimits the 773 decision.
Giving such lesser Tribunal meetings decisionary power about lasting boundaries, which hence would preempt the decisions of other such lesser Tribunal meetings, would be a recipe for needless strife - which the Grand Tribunal would have to sort out later anyway.
So it makes sense - but to my knowledge is nowhere that precisely stated - to assume temporary de facto judicial boundaries determined by the influence of the magi present at a lesser Tribunal meeting. If the presence at such meetings is steady and consistent, also the judicial boundaries of their decisions will become and remain steady and consistent: but sooner or later they will need sanctioning form the Grand Tribunal.
Most of the process of how we get the canon tribunals of 1220 is described actually - but the information is spread out over several books.
Even in 1220 the exact borders of the regional Tribunals are rarely defined precisely and can be pretty fluid.
To a very large extent the borders are defined by regional influence of the covenants that make up the tribunal - i.e. the borders of the tribunal extend as far as needed to cover all the member covenants. As new covenants join or old ones disappear or change tribunal the borders may shift.
So how did they transition from having an East Frankish Empire and Lotharingian to having Rhine, Translyvania and the greater alps?
In fact Guardians of the Forest and Lion and the Lily lay out radically different arrangements of the initial tribunals.
In
865 the Grand Tribunal decided upon
political boundaries of the Tribunals,
rather than relying upon loose affiliations
of covenants. The kingdom of the Germans was called the Rhine Tribunal and
the kingdom of the West Franks was
named the Normandy Tribunal because of
its “North-men” settlers. The kingdom of
Lotharingia was called the Provencal Tribunal, as its center of culture was in the
southern region called Provence. The Britannian (later divided into Loch Leglean,
Stonehenge, and Hibernia), Roman, Iberian, and Theban Tribunals were founded
at the same time, and a coalition of eight
covenants managed to win for themselves
a geographically small Tribunal called the
Greater Alps, the territory of the former
Roman provinces of Rhaetia and
Noricum. Finally, the four covenants in
the Holy Land constituted the Tribunal of
the East (renamed the Tribunal of the
Levant in 1129).
-Guardian's of the forest
The restriction, that any regional Tribunal can only bring three issues to the Grand Tribunal, does only make sense if the jurisdictions and territories of regional Tribunals are roughly set up and sanctioned by the Grand Tribunal before.
So this is one obvious change, exemplifying how the Grand Tribunal got restricted to resolve matters affecting several regional Tribunals or all the Order.
Lion and the Lily p14-16 and Faith and Flame p10 describe how the current Normandy and Provencal tribunals got their current shape, and talks some about the Iberian tribunal as well. Far too much text for me to quote or summarize here.
Transylvanian tribunal got split off from the Thebes tribunal because the original Thebes tribunal was too large and unwieldy. This happened in 964 (TSE p22)
The GotF is the one that I have read most thoroughly, and the border to the East with Novgorod is understood to be fixed and settled, as Lusatia, where Odorpes lies is specified to be very close to the border.
Similarly, Roznov is more or less the border between the Rhine and Transylvania.
One reason which I put a lot of emphasis on borders and their stability is that in my current Saga, Lotharingia has split and while the Rhine would be a natural border between the two Tribunals, there are Covenants and chapter houses on both sides which do not match the river: my party is in Waldheim and would claim a strip of land on the German right bank of the Rhine. A vengeful and spiteful Dunremar is disinclined to acquiesce to their request... The border drawing committee is a looming threat over the Covenant and unbeknownst to them Richenda Spinosa has been sent to evaluate this and draw maps for the Elder Gild.
Yes? Regional tribunals were constituted at the same time as the Grand tribunal, even if their borders weren't always clear.
I have always felt that many of the Tribunals are to large in the area they cover. Much of the area in them is completely uninhabited by Magi of the Order. This means that most boarders drawn on a map are inaccurate and were just extended out to a point somewhere roughly midway between the two nearest covenants of each Tribunal.
Any group that meets the minimum requirements (12 Magi) could easily setup four Covenants in the boarder regions between many Tribunals. Granted there are a few boarders this would not be possible because Covenants are right up against the boarder. Normandy and Provincial for example are like this. However for Normandy there is a huge unoccupied area between the three boarder Covenants and the rest of the tribunal population. If one new Covenant joined them (whether a Provincial or a new one), they would be well within their rights to create a new Tribunal due to the distance between them and the rest of the Normandy Tribunal, along with the difference in culture.
Ultimately this all feeds back into my feelings that the Order is far too low in population for the amount of territory they control. There is over 3,000 square miles and nearly 40,000 mundanes for every Magi just in Europe.
Valid regional Tribunals were 773 defined by (GotF p.140):
Procedures for lesser Tribunals are established: a Tribunal shall consist of at least twelve magi from at least four covenants.
This does not allow the Grand Tribunal to refrain from handling all matters that come up in the Order, restricting their agenda to three issues per lesser Tribunal meeting. There can e. g. be areas for which no Tribunal meeting was ever held between Grand tribunals.
If really needed, it is always possible to call an emergency Grand Tribunal.
Regarding the case for regional Tribunals where no Tribunal meetings have been held between two Grand Tribunals, that can equally well happen in 1220 as in 773. No change there.
The magi do not «control» the territory. Therefore I also do not see the problem. That less than one in 40 000 people has the Gift would also not surprise me.
On the contrary. It makes perfect sense. If that rule was implemented in 773, it would tell the magi to team up in groups of at least twelve magi and four covenants, to prepare their issues. Smaller cliques cannot make proposals. That is a workable scheme. The only decision explicitly said to happen in 865 is the border definitions. Even the requirement that every magus needs to belong to one and only one tribunal is possible without set borders.
Errata for GotF:
"The Partitioning of the Order (pp.15-16): The original name of the Normandy Tribunal was the "Tribunal of the West Franks" and the original name of the Provencal Tribunal was the "Lotharingian Tribunal". Remove the Iberian Tribunal from the list."
Actually by cannon, one in every 10,000 people has the Gift. That roughly 1:~40,000 ratio ignores the mundane populations of Novorod, Levant, and half of Thebes. If you include those areas, the ratios get even more out of whack.
While the Order does not control the mundane aspects of the land they inhabit, they very much control it in relation to magic and other magic users. They need enough Magi to protect and police that area against outside groups. Considering the low ratio of combat Magi verses all the types worthless for this and how slow the Order is to respond to things, the Order would have a difficult time protecting themselves from a concentrated attack by another group.
Additionally all the little sub-groups within the Houses and all the Mystery Cults are limited to no more than a handful of members possible. While interesting flavor wise, in any given game most of them can not exist due to lack of sufficient Magi. Unless of course all the Magi in your game are members of multiple "special snowflake" groups each.
I am bringing this all up because if you are going to go through all the trouble of tearing down and rebuilding all the Tribunals, then you might as well go through the trouble of changing the ratio of Gifted:Mundane and the total membership of the Order. That way you actually have enough bodies to fill the increased number of Tribunal and all those little "special" groups. It would also make a Tribunal in Ireland and Scotland much more capable of supporting an actual population of Magi without almost all of them being transplants.
The thing is that it sn't just about teh names. GotF and Lion and the Lilly assert that the borders of the old tribunals followed the divisions of the Carolinian Empire, then proceed to describe Lotharingia as being Provence, which in fact they were two separate kingdoms on nearly the opposite sides of Europe by the treaty of Prum, prior to that treaty the name was the central Frankish kingdom. So it's a bit like saying that Sherlock Holmes used deductive reasoning when Sir Arthur Canon Doyle then proceeded to describe inductive reasoning. You can say "but it's canon" and be right, but its still just wrong.
Yes, the original Lotharingian tribunal seems to have corresponded with the shortlived mundane Kingdom of Middle Francia, ruled by Lothair I, and this is the kingdom referred to in Lion and the Lily as "Kingdom of Lotharangia".
This kingdom was then split up in 855 by the treaty of Prum into Lotharangia, Provence, and (North) Italy.
Of course, back then they cared less about what a realm was called than about who ruled it, so Middle Francia was possibly sometimes called Lotharangia after its ruler back then. Or perhaps someone found different information in some history book when writing the books.