I would say the most important would be the thriving cities because even if you lose the wealthy merchant class, by budgeting their money and saving what they could they could easily become wealthy again. A thriving city gives more than fund anyways. A thriving city has plenty of food, water, clothes, etc. Things that are needed to literally thrive. They have good education systems, some of the greatest thinkers and philosophers of our time coming from Greece, Rome, and Italy. A lot of art from this time period is still studied today in the most prestigious schools.