Chicago Aristotelian criticism had its origins in the work of a group of critics based at the University of Chicago, of whom the most important was R. S. Crane. Others were W. R. Keast, Richard McKeon and Elder Olson. They constituted an important opposing force to the New Criticism which had become dominant in American universities from the 1940s. The Chicago critics were sympathetic to historical scholarship but, unlike most traditional historical critics, they were also concerned with the need for literary criticism to develop a coherent theoretical basis. They argued that the kind of formalist approach favoured by the early New Critics was inadequate because it failed to take account of traditional poetics. They particularly stressed the importance of Aristotle's Poetics since it was fundamental to literary study that one should distinguish between different types of literary discourse and not treat them as if they had been constructed on identical principles.