The "Rules of Theology" by Alain of Lille (died 1202/03) is one of the most influential texts on scientific theory and ontology from the second half of the 12th century. In response to the scientific transformation of the seven liberal arts as well as ethics and natural knowledge, and drawing on newly accessible ancient and Arabic sources, Alain develops an axiomatic model of science in the famous prologue of the "Rules." He applies this model in logically interconnected propositions to philosophical theology and systematically reconstructs it in the form of a Neoplatonic ontology. The text vividly illustrates the changes in the self-understanding of the Western Middle Ages that led to the formation of universities and, in philosophy, to the "second beginning of metaphysics.".