Van Dyck masterpiece discovered - Telegraph At the same time the archive at the National Gallery was used to verify the sitter was Olivia Boteler Porter, a lady in waiting to Henrietta Maria, the wife of Charles 1. Then the thick layer of varnish and grime was removed which enabled the picture to verified as a Van Dyck Christopher Brown, Director of the Ashmolean Museum of Art and Archaeology. "To find a portrait by Van Dyck is rare enough, but to find one of his 'friendship' portraits like this, of the wife of his best friend in England, is extraordinarily lucky," Dr Grosvenor said. Although as part of our national heritage values are irrelevant, for insurance purposes it should now be valued at anything up to £1 million. Had it appeared at auction as a copy, and in its dirty state, it would probably only have been estimated at about £3-5,000.