  Because of considerations of space, we shall not discuss these related topics here, nor can we refer to all the issues about categories raised by medieval authors or mentioned above. However, the conceptual framework of issues we have introduced should help in the understanding of how categories are approached in the Middle Ages and the differences between the medieval approach and those taken in other periods of the history of philosophy. We begin with the classical background of the discussion of categories in the Middle Ages. This consists primarily of Aristotle, who is responsible for the first treatise on categories ever written.