During the late Middle Ages, Northern and Central Italy became far more prosperous than the south of Italy, with the city-states, such as Venice and Genoa, among the wealthiest in Europe.
Some of the first major city-states were port cities that acted as trade centers, like the republics of Pisa, Genoa, and Venice. Their wealth came from international trade routes we call the silk roads, connecting European and Asian markets thanks to the massive Mongol Empire that opened up Eurasian trade.