Why is it canonical?

One of the most famous sculptural works in Western history, Michelangelo's David marks a watershed moment, when European artists ceased to replicated or mimic classical sculptural and began to compete with it in terms of excellence on their own terms. Michelangelo's massive statue, which came to symbolized Florentine republican virtue, stands like a guardian of the people, and was unique due to the naturalistic depiction of the masculine form at such an incredible scale.