Thesis advisor: Boyd Taylor Coolman / Richard of St. Victor is known primarily for two arguments from his book On the Trinity. The first is that the relationship between the Father, Son, and Holy Spirit can be understood from the logic of love, which tends toward sharing with others. The second is that a divine person (persona) is an “individual existence of a divine nature,” a revision of the definition of personhood given centuries earlier by Boethius. Fewer contemporary theologians are familiar with the third major innovation Richard makes in this work. In his description of love among the trinitarian persons, Richard organizes the three loving divine persons according to three modes of loving: gratuitous love (amor gratuitus) identical with the Father, owed love (amor debitus) identical with the Holy Spirit, and love mixed from both (amor permixtus) identical with the Son. The most striking—because the most apparently problematic—part of this scheme is the nomination of amor debitus, owed love, as a mode of loving proper to the Trinity. Presenting the apparently contradictory combination of owing and loving as a love proper to God as God, the conundra raised by Richard’s use of this phrase were interpreted away by his scholastic readers in a way that buried the potential of his insight for discussions about the nature of love called divine. My dissertation analyzes the meaning of amor debitus to reframe and re-present Richard’s arguments in On the Trinity with Richard’s radical claim about the nature of intra-trinitarian love in clearer view. I argue that the notion of owed love represents a class of experience which is distinct both from the obligation of a command (typically associated with debitum) and from the freedom of an unaffected choice (typically associated with amor). Amor debitus fuses the quality of the command or commanding conditions with a freedom that is not intrinsic to these prior conditions, but does not leave them behind. Richard’s link between owed love as a personal property in the Trinity and as the norm of human love for God gives Richard a fresh approach to the idea that “God’s love has been poured out into our hearts through the Holy Spirit” (Rom. 5:5), and therefore also to the longstanding Christian claim that human love is owed to God, ordered to neighborly service, and free. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Theology.