Treaty Of Houses
Research by Merit on the formation of the current Treaty of Houses
The houses at the time just had name names. They tended to compete in a bunch of things all at once, and whichever house was richest was in charge. A lot of effort was spent in competitive money-making, but a lot of effort was also spent in arguing about exactly how "richest" should be counted, because there were multiple resource stats.
At some point, two different houses both triggered the "I'm the richest" mechanic to take over from the third, and when neither of them backed down, it triggered a Treaty of Houses.
There was about a week of politicking and favormongering and building the new rules; the main thing that came out of it was that direct competition in all the same areas was tedious, so the decision was to go for monopolies. The two richest houses had both gathered a lot of favors and support to cash in at the final declarations.
House One declared itself to have a monopoly on the money trade, concluding that this would give it an unbeatable lead in all the things that mattered.
House Two, thinking a bit outside the box, and understanding where true power lies, declared itself to have a monopoly on the military.
Then the House of Hon'eth, smaller but having done well in favor trading (including supporting both One and Two) declared itself to have a monopoly on governance.
And so was the Third Treaty of Houses signed.
That's basically the story as Merit remembers it; the research has a lot more detail and sharp corners, and goes into a little more confusing detail about how the houses gave up their names and chose different names, and the House of Hon'eth basically declared via fiat that their name had been the House of Hon'eth before, and it's not clear what their name *actually* was before, so good on them for such a propaganda coup.