What dictates a popularity of an art style in a certain period
What are the most common influences on art in a certain period?
E.g., what made realism so popular in the time that it was active? I know that the goal of it was to show the lower casts of the society and how they lived, but why was it popular at the time? How does the culture influence the art? I would appreciate some examples. I'm particularly interested in what kind of art style would be present in a period of time where nobles are trying hard to put a divide between themselves and lower casts (classes) of society.
(I do have a background in art theory, but I am not an expert in the field.)
Also, this is my first question, so if I did something wrong, please don't be mad.
Edit*
The world my characters are living in currently is at least partly feudal. I am mostly interested in figurative art and how it would be affected, particularly paintings and statues. The nobles have existed for quite some time, not always having the same influence on the state of the country. In the period the book is set in they have been fighting for some time to keep the magic away from anyone else. This includes 6 rich families, that have gotten to be in the good graces of the ruler of the country. (keep in mind that there are also noble families that have been recognized by the ruler and they serve as vassals to the bigger royal families, but they do not have access to the magic that the <PERSON> families have.) 200 hundred years ago there were guilds that formed that allowed anyone rich enough to practice magic with this came taxes for the noble families that were no longer in a priviliged state that they once inhabited. This was all caused by the ruler of that time wanting to create power in the country. The nobles fought to stop this and through unspecified circumstances they have. 878
The thing is every part of the country is under rule by one of these royal families. And the ruler is not particulary thrilled to make any of them their enemies. So they have went along with this for some time. Currently they aren't paying taxes they marry among themselves and if one of their vassals is shown worthy they will marry one of their daughters to them, but the men from the vassal family will take the woman's name and live with them. Artists generally can come from anywhere, they just need to have a proper education from a recognized master to be successful. They generaly come from noble born families that have the money to pay for the education. They are treated with respect from the nobles and commonfolk alike, but they don't necessarily need to be part of either one. Also anyone who has enough money can buy a sculpture or a painting.
The reason why my question was very bare-bones and not directly related to my story is, I wanted to know what most often affects art (figurative) to decide for myself what paintings and sculptures will depict in my story and what will affect them.(Also I have not completely built the culture yet, so some things I couldn't explain.)
Since this question will probably devolve into a discussion rather than a clear-cut answer, it might be best if examples from history were used rather than theoretical ideas. (Answers to: Why the baroque period was so dark with only a single source of light, or why rococo depicted mostly nobles in their day to day activities etc.) 412