On the bus ride home tonight, it occurred to me that a better way of approaching the Seven Cities setting would be to come at it from the perspective of play than concept. I.e., instead of starting with the magic system, I would do better to start with the major geopolitical conflicts informing the setting, conflicts that would make for interesting sessions.
Here's what came to mind as a result of this insight:
1. Led by seven powerful sorcerers, the ancestors of the Seven Cities citizens arrive at the mouth of a great river basin. They are fleeing some great conflict or evil in their ancient eastern homeland. (Yes, Kevin Crawford's Red Tide is my inspiration here.)
2. As the Seven Cities folk spread out across the basin, founding new cities, they come into conflict with the aboriginal clans. The locals are no match for advanced sorcery and are eventually conquered. They become the ancestors of the laborers who grow the cities' food, mine their ore, chop down their wood, and clean their homes. Periodically there are workers' revolts and uprisings.
3. The most savage of the aboriginals refuse to be conquered and flee into the mountains north of the basin. Their descendants are the barbarian tribes that periodically harass the northern cities before being driven back into the hills and mountains.
4. There also aboriginal tribes dwelling in the great southern desert that sits between the river basin and the territory of the expansionist Azure Empire. The sorcerers never bothered to conquer these tribes, having no interest in their harsh desert lands. As a result, the tribes continue to raid the southern cities and attack caravans moving north and south through the desert.
5. The Azure Empire would very much like to conquer the Seven Cities and take their magic lore for its own. Imperial sorcerers aren't a match for the Seven Cities wizards, though, and the Azure Empire has opted instead to achieve its goals through destabilization, infiltration, and treason.
6. One of the Seven Cities is "the good guy." Its citizens treat their workers well, try to maintain peace with the local barbarians, and work to unify the region against the Empire. Needless to say, they're the primary target of rabble-rousers and enemy agents.
7. One of the Seven Cities is "the bad guy." Its citizens are not just interested in political power in the region, but are actively messing with forces best left alone. This is the nasty, decadent piece of work in the setting.
8. The remaining five cities are in a state of political flux, constantly forming and breaking alliances in attempts to dominate the river basin.
This history gives me a number of story elements:
1. What caused the citizens to flee their ancestral homeland? At the campaign's start, this will be a mystery. It may stay that way unless players are particularly interested in revisiting it.
2. The conquered locals are a source of unrest that players will inevitably find sympathetic.
3. The northern barbarians and the southern barbarians are not only points of origin for the most archetypal of S&S characters, but are also adventure generators in their own right. Maybe they're uniting to make a major push for revenge (and are seeking common cause with their "cowardly" cousins in the lowlands), threatening the caravan trade, etc.
4. The Azure Empire is always there, lurking in the background.
5. The good city provides players who want to be the good guys with a patrons. Players who like to live on the shady side of the law might opt to help conquer it instead.
6. The bad city is the mad dog that needs putting down--it's the Joker, and it just wants to see the world burn. Maybe it's gotten in touch with demons or maybe it's reestablished connection with whatever forced the ancestors to flee in the first place.
7. The petty intrigues of the remaining five cities are a source of constant story hooks, big and little.
With this framework in place, I can start to figure out the game-related stats for each culture involved in the setting (smallfolk, northern barbarians, southern barbarians, Azures, city-dwellers with an option to further subdivide into seven urban cultures). I can also decide what magic traditions to associate with each city. Two things that immediately come to mind: Drimshy maintains its focus on wind and water magics--it's the oldest of the Seven Cities, sitting atop the landing site of the refugee fleet. I also think that I need to avoid the clichéd approach of making the necromancers of Achiroth the crazy bad guys; they're either one of the "neutral" five or (if I was feeling particularly cheeky) the good guys.