A specialist in 17th and 18th century Spanish painting, he has been Director of The Wallace Collection since October 2016. He has previously worked as Head of Conservation at the Dulwich Picture Gallery, as Curator at the National Gallery in London and as Head of Conservation at the Bilbao Fine Arts Museum where he is involved in its museographic reorganization. Co-curator of numerous exhibitions among them: El Greco, Caravaggio, the last years, Velázquez and Murillo and Justino de Neve. In 2009 he organized his first sample: The Sacred Made Real, at the National Gallery, where he also presented Goya: The Portraits in 2015. He collaborates as scientific director in the production of the documentary El Greco: painter of the invisible presented at the Prado Museum on the occasion of the centenary of the artist. In 2018 he organized at the Dulwich Picture Gallery Ribera: Art of Violence, the first sample in the UK dedicated to the Baroque painter. 

D. in Art History from the Universidad Complutense. He has been a Professor at the Universidad Autónoma de Madrid since 1976 and Full Professor since 1993. Specialized in the history of architecture and Spanish art of the XV and XVII centuries, with special attention to the figure of artists such as El Greco and Velázquez. He has to his credit almost three hundred publications and research articles in these fields. He is also the curator of numerous exhibitions, among them: Charles V. Arms and Letters, El Greco: The Apostles. Saints and "madmen of God" and The Greek of Toledo. He is a member of the Scientific committee of the Centro Internazionale di Studi di Architettura Andrea Palladio in Vicenza and publisher of its journal Annali di architettura. He is a Corresponding Member of the Royal Academy of Fine Arts and Historical Sciences of Toledo and an Elected Member of the Royal Academy of History.