Summary: The doctrinal developments between the 13^th and 14^th centuries concerning the ‘subject’ of theology, offer interesting contributions in order to understand the relationship between philosophy and theology. First, until the seventies, in the 13^th century, the theologians use the current philosophy – the greek-arab aristotelism – as a basis for the elaboration of their own theology, resulting in a plurality of theologies. Thomas Aquinas even individuates a ‘subject’ for the theology symmetric to that of the philosophy before Aristotle. Second, Scotus elaborates a theory on the plurality of theologies and their ‘subjects’, in correspondence with the crisis of the Aristotelian epistemology. In this way he reaches three important goals: 1. To elaborate an epistemology adapted to the nature and end of theology; 2. Shows that the theology needs metaphysics, because this provides the conceptual tool (l’ens infinitum) which helps to objectivate contingent and no-contingent truths; 3. It is to do a ‘revolution’ of the current medieval metaphysic building it over mere ontological basis.