The Maritime Republics in Italy have always fascinated me. (for those of you who don't know, this refers to the Italian citystates of Amalfi, Gaeta, Ancona, Ragusa, Pisa Genoa and Venice)
These states compete with each other, and form a shifting web of alliances and warfare. It is remarkable how through commercial power single cities were able to build armies which toppled Empires and could fight off mainland European kingdoms.
As these states often were in alliance with eachother, I was thinking that perhaps a permanent alliance or even a union between these cities could come about. Since their competition was based on protecting their monopolies. perhaps foreign threats which cause then to band together temporarily OTL may result in agreements which prevent the need for further competition. This may cause a permanent military alliance, some sort of commercial regulatory body between states, and possibly even a league featuring effectively non-dynastic (though still autocratic) leadership.
Does anyone forsee a way this might come about?