 The ancient practice of collection and division, and especially the proclivity to call both the products of collection and the things to be divided wholes, has a lasting influence on medieval mereology. For medieval philosophers a variety of items can be wholes. Universals, concepts, material objects, masses (such as water or gold), souls, and time can all be wholes—and this is only to mention some of the more common items studied by medieval philosophers. Thus, in general, anything that is composed out of other items or that can be divided into other items is a whole. But there are two important qualifications.