Richard of Saint-Victor, On the Trinity: Prologue and Six Books

Richard of Saint-Victor's On The Trinity from the 12th century is a main source for our understanding of a leading intellectual tradition of the Western world in which love was regarded the highest and the best in the human world and therefore also was the reality in which the highest and the best in the universe, God, was to be seen. Richard understands human love as interpersonal so that love must be realized between two persons, but for being the highest love that excludes any private and selfish love, both loving persons must share their love with a third person.