THIS STRIFE IS GOOD FOR MORTALS
And it seems to me that there would not have been so fine a bloom of perfection on Plato's philosophical doctrines, and that he would not in many cases have found his way to poetical subject-matter and modes of expression, unless he had with all his heart and mind struggled with Homer for the primacy, entering the lists like a young champion matched against the man whom all admire, and showing perhaps too much love of contention and breaking a lance with him as it were, but deriving some profit from the contest none the less. For, as Hesiod says, 'This strife is good for mortals' (Works and Days 24, at Perseus). And in truth that struggle for the crown of glory is noble and best deserves the victory in which even to be worsted by one's predecessors brings no discredit.
To see that competition in action there is no better place than Florence. While it’s fashionable to disdain the idea of the city on the Arno as the birthplace of the Renaissance, I think it indisputably is that (even though one has to acknowledge the role of cities like Ferrara, Milan, and Venice). And beyond the place of humanist studies in Florence I would accord that city the palm for reinvigorating classical art because of its relentless critical culture. The Florentines were famous for their “good eye and evil tongue,” which meant they could spot both the good and the bad, and they knew how to say it devastatingly. This did not hurt artists’ self-esteem as we would be so afraid to do, but it gave them pause before they put their work up for criticism. Implicitly, we are talking about a public art—even the art of the Medici’s private realm was seen by many, especially those who wielded a public pen. And we are talking about having rational standards of accomplishment and judgment.
But competition in a city like Florence wasn’t primarily about tearing down, it was about pushing, stretching, advancing. In a competitive culture with actual standards of Beauty artists know what they’re aiming for, and their predecessors and colleagues provide measures of achievement (not today’s data-driven “metrics”). I can tell you from my own experience that, whether it is in learning a language, drawing the figure, or designing an urban plan, having someone to aspire to makes me better. Some thoughts on how this worked (and didn’t) in Florence can be found in my book from Ashgate, and as of 4 June on the Artist Daily blog.
 Longinus, On the Sublime, trans. W. Rhys Roberts, XIII, my italics