From the introduction:
Parsantium: City at the Crossroads is a sourcebook for use with all editions of the world’s most popular fantasy roleplaying games. Parsantium is a melting pot, a cosmopolitan place where trade routes meet and where great cultures collide. Inspired by Byzantium with its rich Greco-Roman heritage, it also incorporates characters, monsters and magic from the Tales of the Arabian Nights, ancient India and the Far East, alongside more traditional European fantasy elements. In Parsantium you’ll find evil cults, scheming politicians and nobles, rakshasas and serpentfolk, ancient dungeons beneath the city streets, and powerful criminal gangs, not to mention gladiators and chariot racing. In fact, Parsantium (and this book) contain enough adventure hooks, patrons and adversaries to keep most adventuring parties busy throughout their careers without ever having to venture outside the city walls.
This sourcebook is intended to be edition-neutral, notwithstanding the Pathfinder compatibility logo on the cover. There are very few stats in the book and those that do exist are intended to give an idea of the relative difference in power levels between, say, Sergeant Saurish of the City Watch (LG male human fighter 4) and Tapasranjan, Grand Master of the Esoteric Order of the Blue Lotus (LG male vanara sorcerer 19). It should be easy for the GM to change the levels of the NPCs to match a chosen game system or PC party strength.