During and after the Liberation War, most aristocrats of the Flannish Cities region either fled or were killed. Some, however, managed to stay and arrange themselves with the new powers that be, publicly accepting the new social order and giving up their titles while less publicly striving to keep as much of their old wealth and influence intact. The strong economic growth of the region saw their fortunes rise, even though they lacked the control they used to have. But it didn't take long to reestablish their old ties, and behind their facade of being respectable (if particularly wealthy) citizens, they continued their dynasties of blood as if nothing happened. Over the course of decades, the exiles were invited back and integrated back into their circles, and their descendants were married to other scions of noble blood, only permitting marriages with commoners in the case of particularly spectacular wealth or political influence. Thus, a secret parallel society was born, which kept out of the eyes of the public while slowly growing in power and wealth.
When they refer to their refined circles at all, they call themselves the Highborn - but most of the time no such appellation is necessary. After all, they know each other well enough - they went to the same exclusive private schools, they all attended their common debutante balls, they marry into each others' lines and they meet in the same, exclusive clubs away from the eyes of the private public. And while they still have fierce feuds and rivalries between different family lines, they realize that they need to stick together, and they cooperate their efforts to increase their power. In particular, they strive to gain control of large and popular newspapers, as they know that if they ever want to return to public control they need public opinion on their side, but they also invest heavily in financial institutions, real estate, and anything else that will not only bring them wealth but power.
Their biggest stronghold is the city of Leconte, in the Parginian Rim, whose ruler is among their biggest supporters. Staying in Lecomte during the ball season at least once in one's life is expected of the Highborn, and most make the journey several times to build valuable connections to their peers.