 Peter Abelard (1079–1142) was one of the first original medieval logicians in the Latin West. His most thorough treatment of the theory of the syllogism can be found in the Dialectica, though he occasionally discusses it in other works as well, such as the Logica ingredientibus (Minio-Paluello 1958). It is only in the Dialectica, however, that the theory is outlined in full. 