A society has to be super rich to support artists and elaborate building projects and to feed scholars who translate and comment on thousand-year-old documents. And the Italian city-states were very wealthy for two reasons. First, many city-states were mini-industrial powerhouses, each specializing in a particular industrial product, like Florence made cloth, Milan made arms. Second, the cities of Venice and Genoa got stinking rich from trade. Genoa turned out a fair number of top-notch sailors, like, for instance, Christopher Columbus, but the Venetians became the richest city-state of all. As you'll remember from the Crusades, the Venetians were expert sailors, shipbuilders, and merchants, and as you'll remember from our discussions of Indian Ocean trade, they also had figured out ways to trade with Islamic empires, including the biggest economic power in the region, the Ottomans. Without trading with the Islamic world, especially in Pepper, Venice couldn't have afforded all those painters, nor would they have had money to pay for the incredibly fancy clothes they put on to pose for their fancy portraits.