 He asserts that the philosophies of Platonism and ancient Neo-Platonism, the works of Plotinus and Pseudo-Dionysius the Areopagite, the texts of the Church fathers and the liturgy offer the keys to the understanding of El Greco's style.Summarizing the ensuing scholarly debate on this issue, José Álvarez Lopera, curator at the Museo del Prado, Madrid, concludes that the presence of "Byzantine memories" is obvious in El Greco's mature works, though there are still some obscure issues concerning his Byzantine origins needing further illumination.El Greco was highly esteemed as an architect and sculptor during his lifetime.