The podcast "The Tides of History" had a bunch of episodes on early modern Italy in general and Venice in particular, which were really eye-opening.
The other interesting fact about the Italian mercantile city-states is that many of them lasted an amazingly long time. The republics in Venice and Genoa, for example, were only extinguished in 1797 by Napoleon!
And if you go on vacation in the region around Venice (Veneto) you'll see so many historical buildings with engraved the San Marco's lion (the emblem of Venice) and flags that it feels like it ended in 1979. It also gives a feeling of the wealth of the Republic of Venice.
The other interesting fact about the Italian mercantile city-states is that many of them lasted an amazingly long time. The republics in Venice and Genoa, for example, were only extinguished in 1797 by Napoleon!