Complex sentence: Blunt was Professor of the History of Art at the University of London, director of the Courtauld Institute of Art, and Surveyor of the Queen's Pictures; his monograph on Poussin (1967) is still widely regarded as a watershed book in art history.
Split into simpler sentences: Blunt was Professor of the History of Art at the University of London, director of the Courtauld Institute of Art, and Surveyor of the Queen's Pictures. His monograph on Poussin (1967) is still widely regarded as a watershed book in art history.