This article offers a reading of Richard of St Victor's medieval treatise On the Trinity. It suggests that while Richard interrogates the question of trinitarian personhood in innovative ways, his contribution lies in the way he emphasises how nature influences the criteria for personhood with respect to different modes of existence. Thus, while human personhood shares certain features in common with divine personhood, the two concepts must remain distinguishable with reference to the type of natures they uniquely ‘person’. This conclusion may serve to chastise modern forms of trinitarianism which assume ‘univocity’ of divine and human personhood too hastily.
