Sir Denis Mahon, who died in 2011 aged 100, was a great collector and a renown art historian, specialist of 17th century Italian paintings, notably Guido Reni, Caravaggio and Nicolas Poussin.
For Michael Kitson, Claude Lorrain specialist, teacher then deputy director of the Courtauld Institute, «Denis Mahon is the greatest art historian-collector of our time, maybe of all times.»
Mahon’s ability to sort out the chronology of an artist’s work through meticulous visual analysis conducted him to challenge Blunt’s chronology in the catalogue of the 1960 exhibition at the Louvre.
He also managed to convince Poussin’ specialists that the Landscape with Diogenes was painted almost 10 years after the previously accepted date of 1648.
He wrote several books, notably on Poussin’s work.
• Sir Denis Mahon (The Telegraph, Art obituaries)