Transformation, participation and plurality: The Cappadocian heritage for Systematic Theology in the third millennium. The aim of this article is to demonstrate how Systematic Theology in the third millennium utilises facets from the legacy of the Cappadocian fathers. The focal point is the influence on present-day Trinitarian theology. Aspects which are discussed include matters of metaphysics, philosophy, morality and spirituality. The influence of the legacy of the Cappadocian fathers concerns the challenge which diversity and plurality create in systematic theology. This legacy is explored by means of the ‘lived experiences’ of the life stories of the Cappadocians. These narratives illustrate a shift from the ‘impersonal’ to the ‘personal’, from ‘disengaged abstraction’ to ‘relational participation’. The latter is referred to as ‘a pastoral doctrine of the Trinity’ by Paul S. Fiddes. The emphasis on ‘economical ontology’ confirms the Cappadocians’ relevance for a present-day ethical discourse and the ‘aesthetics of a feeling for the Other’.