I'm gonna go with something Celt-ish then.
Peasantry and guildmen, unite!
Cast out the feudal nobility and seize your freedoms for yourself!
And then de facto enshrine the merchant class as the new nobility by virtue of wealth instead of blood, but we won't talk about that.
EDIT: putting the signup here rather than double-posting
Name: Finglas 'Forktongue', Reeve-Prince of Firdun
Age: 47
Gender: Male
Skills: Civil Administration, Demagoguery, and Espionage
Bio: Firdun's fortunes have long been assured by virtue of its commanding position; sitting at the southernmost point of the Androx Peninsula, it is a major player in the trade of the southern coast, with ships moving through its port even along the River Maltos to Frostlake itself. The wealth that passes through the city, its relatively secluded position, and the religious differences the city has compared to its neighbors have led over the years to a greater degree of autonomy among the lower classes in the city than perhaps anywhere else, and served as the root of a nascent movement towards self-rule by its freemen. In a move to stave off a massive peasant rebellion decades earlier, this culminated in a royal decree that the city would henceforth be a Free City, whose reeve would be elected by acclamation, not appointed - and which has subsequently led to a lively political life, whose violence has largely been directed inwards at the city's great families, and not outwards at the nobility.
This, however, changed with the election of Finglas to the reeveship. The thirdborn son of one of the most prolific shipping magnates in the southern reaches, his family's almost obscene wealth, coupled with the gift of the gab and a devious insight into the slights and privations endured by the city's freemen leading to a nearly preternatural gift for rabblerousing, combined to pave the way for election into ever-greater roles in the city's government, culminating in his ascension to the reeveship two decades earlier.
Since then, he has aggressively expanded the city's influence, going so far as to annex the lands north as far as the Isthmus of Andras, and building the Long Walls across it, ostensibly merely to mark the extent of Firdun's expansionist fervor, but which has been more cynically viewed as the first steps towards rebellion.
Certainly the cynical perspective has been advanced - three years ago, he proclaimed himself first of the 'reeve-princes', claiming himself the equal to any of Wintreath's princes save by blood, a move which has garnered no small amount of scorn from the nobility (tempered from violence only by the threat of withdrawal of financing and guildman strikes), but which has inspired similar movements in Wintreath's other great cities, and culminated in his proclamation of a United Free Cities, an organization by which the wills of the people might be heard just as loudly as that of the nobility.
OOC notes:
I use 'princes' not in the sense of 'prince of the blood', but rather 'ruler of a principality', as in the sense of Princes of the Holy Roman empire.
I have done my best to adhere to Weissreich's map, although to fit the Celtic flavor I was going with, I changed the name of the port-city while keeping the original name to describe the peninsula it sat upon.
I also straight-up made up history, and if this flies in the face with as-yet-unwritten canon I can rewrite it whenever. But I tried to create a practical grounds by which the merchant class might rise up into a practical political entity in the face of the entrenched nobility, and hopefully I've done so.