This article aims to provide a metaphysical elucidation of a specific model of the doctrine of the Trinity: Monarchical Trinitarianism, within the formal, neo–Aristotelian ontological and metaphysical framework of Jonathan Lowe (i.e. his four–category ontology and serious essentialism). Formulating the model through this ontological and metaphysical framework will enable us to explicate it in a clear and consistent manner, and the important 'multiple–natures' problem raised against the proposed model will be shown to be ineffective.