In the Physics, Aristotle says that there is no change associated with the category of relatives. In this paper, I examine a widespread but neglected strategy that medieval thinkers use to understand Aristotle’s claim. According to this strategy, which I label initial presence, if there is no change in the category of relatives, it is because the relation-properties are already present in their subject as soon as the properties on which relation-properties are founded exist. Appreciating the importance of this strategy (...) is crucial not only for understanding medieval theories of relation but also for assessing the credibility of arguments used in the secondary literature to interpret medieval texts, in particular a well-known passage from Thomas Aquinas’s commentary on the Physics. (shrink)