How were the patronage of the arts by Italian Renaissance rulers similar to that of dictators of the 1930s?

Answer 1

Or similar to any other period of history?

Check out some of these, if your library has them:

Brandon Taylor, Art and Politics: Proceedings of a Conference on Art and Politics (Winchester School of Arts Press, 1980).

David Mateer, Courts, Patrons, and Poets (Yale University Press, 2000).

Laurence Fontaine, History of Pedlars in Europe (Duke University Press, 1996).

Paul Dimaggio, Nonprofit Enterprise in the Arts: Studies in Mission and Constraint (). The examples of Germany and the Netherlands after WWII specificly describes part of the role of government subsidized art (p. 292).

Essentially, two general functions are at play. Some of it is akin to the ancient Roman satisfying the populace with "bread and circuses". Some of it is akin to Hitler employing Goebbels for propaganda minister and the innovative Riefenstahl--arts at work in selling ideas, just as the proverbial "Madison Avenue" advertising and marketing experts do today.