The theme of research in this paper is the triadology and triadological terminology of St. Augustine and its relationship with Cappadocian triadology. The focus of the research is on the use of the terms „substantia vel essential“ and „substantia vel persona“ in St. Augustine’s triadology — in the context of the question of whether he understood the Cappadocian conceptual revolution, i.e. the sense of the Cappadocian conceptual revolution in triadological terminology (their distinguishing between essence and hypostasis). It turns out that Augustine’s confession that he did not understand the Cappadocian distinction between essence and hypostasis (in the fifth book of his De Trinitate) is not based on his alleged ontological diminution of personality (Latin persona). Such an interpretation is a prejudice based on the so-called de Regnon’s exegetical paradigm. Despite the fact that at first he did not understand the Cappadocian distinction between the terms essence and hypostasis in triadology, the Cappadocian triadology itself was not disputable for Augustine, as was the case, for example, with Blessed Jerome. Augustine never understood the Cappadocian phrase „three hypostases“ in the Arian sense, as Jerome did. Augustine’s correct interpretation was most probably influenced by the writings of his famous predecessor, Saint Hilary of Poitiers — De Synodis. Finally, the paper shows that Augustine, during the writing of his De Trinitate (in the seventh book), came to a complete understanding of the Cappadocian equating of hypostasis and personality („substantia vel persona“). However, Augustine did not give up the old practice — „substantia vel essentia“, believing that he should remain faithful to the inherited Latin practice.