Who is not familiar with Aristotle's Poetics? Who is not familiar with modern poetics, if only Boileau's Art poétique? But apart from specialists, who is familiar with the poetics of the entire period between classical antiquity and modern times, between Aristotle and the Pléiade or Boileau? Yet, this period extended over two thousand years. Furthermore, it possessed its own poetics, governed by the strictest principles, worked out to the last detail. It may be divided into two great epochs: the end of Hellenic-Roman antiquity, on the one hand, and the entire Middle Ages, on the other. The poetics of these two epochs were very similar, since the second depended in great part on the first. Nevertheless, they present differences which oblige us to study them separately.