When thinking about Safelster we often immediately jump to Renaissance Italy (lots of little city-states threatened by imperial conquest), but another potentially interesting inspiration is the city-states around Lake Texcoco in the 13th and 14th centuries, prior to the Aztec Triple Alliance.
As Wikipedia puts it:
After the end of the Toltec empire in the 13th century and the decline of the city of Tula, the population shifted once again, this time to the lakes region of the valley. With this migration came the concept of a city-state based on the Toltec model. By the end of the 13th century, some fifty small urban units, semi-autonomous and with their own religious centers, had sprung up around the lakeshores of the valley. These remained intact with a population of about 10,000 each under Aztec rule and survived into the colonial period.
There is so much more to draw on for fantasy than Europe! Wander around the Mesoamerican sections of any good museum, check out the Silk Road, Gandhara, Hittites, and Mesopotamia! Ponder Alexander and his successors. Go to a pueblo or check out a cliff dwelling. Let your fantasy wander and be inspired broadly!
Note that I don’t suggest looking at Lake Texcoco because I think the Safelstrans are similar to the Mesoamericans. Rather, look at the Valley of Mexico as an alternate example of competing city states, jostling against each other, and how they function – as an alternative to Renaissance Italy, whose familiarity can be overwhelming.