William Shakespeare was referred to as "an upstart crow" by whom?

Robert Greene called William Shakespeare "An upstart crow." This statement refers to a historical incident where Greene, a contemporary playwright, criticized Shakespeare for his rising success and lack of formal education. The phrase "upstart crow" implies that Greene saw Shakespeare as an arrogant and unqualified newcomer to the theater scene. This insult highlights the rivalry and competition that existed among playwrights during Shakespeare's time.