 Abelard is also associated with the history of modal logic. He is famous as the philosopher who introduced the distinction between de dicto and de re modal sentences. The basic notions of Abelard’s modal theory are to be found in the introduction to Chapters XII and XIII of his longer commentary on Aristotle’s De interpretatione (ed. Minio-Paluello 1958). Abelard concentrates his analysis on the logical structure of modal sentences, introducing some new distinctions and concepts that were later commonly used by medieval logicians.