If you've ever taken an art history class, or even one in art appreciation, you know that the era they call "The Renaissance" is held in reverence something just short of the Second Coming. This "reawakening" is set up on a historic pedestal intended to inspire a worshipful awe as everyone from the highest high-priest-art-history-professor to the lowest graduate-student-teaching-assistant-altar-boy marches around it swirling incense, and sprinkling holy water while intoning the words "Raphaellllllll...Michelangelooooo... Leonardoooooo". Meanwhile all we art appreciators genuflect and murmur an appreciative background litany of gasping ooooo's and ahhhhhhhh's at every Madonna, David, and Mona flashed upon the screen for us to identify, categorise, and immortalise. Then when it is all done, we take an essay test and I'll bet dollars to donuts the very first question is: "Discuss the causes relevant to the development of the Renaissance and their effect upon the various forms of art of the time." (Or something to that effect.)
Well, let me answer the first part of that question in one word--money. Of course that's a gross oversimplification and would rate a single word response--explain! Actually, it's not only an oversimplification, it's a bit inaccurate - credit would be a better response. Now, let me explain. During the Middle Ages, there were two-forms of trade--gold, and barter. Gold was in short supply until the New World explorers robbed the native Americans and flooded Europe with it. And Barter was terribly inefficient. Credit, on the other hand (basically letters of credit), couldn't be easily stolen, weighed very little, and was an efficient way of transferring huge amounts of wealth. Which brings us back to the original answer--money. Without large amounts of it, there were only fortress prisons in which those who had accumulated some wealth relied upon ugly stone walls to avoid being murdered in their sleep. However, when it became economically feasible to enclose an entire city in fortress walls, then those with money could begin to relax and enjoy it, which meant a craving for beauty that meant art. The city of Florence, Italy, is a classic example.
Italy (and its newly minted middle classes), jutting its booted peninsula out into the maritime trade lanes of the Mediterranean, was ideally suited to taste and enjoy this new-found prosperity first. They spent the thirteenth and fourteenth centuries accumulating wealth and the fifteenth and sixteenth centuries enjoying it. In Florence, even though the palazzos of the Medici and other wealthy families still have a prison-like quality to them, inside, as they open into delightfully sunny courtyards, there are windows, which mean light--light to see paintings hanging on walls, to weave tapestries, to admire garden sculpture, fountains, and manicured landscapes. And with wealth comes time--time to enjoy reading and writing poetry, music, great novels, opera, and high fashion. All of these things come together to define the Renaissance and to impact the arts. So, the next time you take an art history course, and it comes time for the final exam, just cut and paste this explanation and you'll be home free.