Nieuwenhuys, Christianus Johannus; Nieuwenhuys, Chrétien Jean
A Flemish dealer (born Christianus Johannus Nieuwenhuys) who later settled in London, Charles J. Nieuwenhuys took over the art dealing business begun by his father, Lambert Jean Nieuwenhuys, in Brussels in 1805. François, Charles' brother, ran the office in Paris, and Charles was succeeded in his business by his son after his death in 1883. According to a brochure on Rubens produced by Duveen Brothers, Inc., Nieuwenhuys "was a well-known art authority and dealer of Amsterdam, Brussels, Paris, and London, and wrote several works on painters and collections, his best known book being A Review of the Lives and Works of the Most Eminent Painters, London, 1834. During his lifetime he was regarded as one of the leading authorities on Dutch and Flemish art, and it was to him that many of the great English and foreign collections owed either their origin or many of their choicest treasures. He had much to do with the buying for Sir Robert Peel, and the King of Holland. It was he who acted for the Berlin Museum in the acquisition of the celebrated Van Eyck Altarpiece."
Sebag-Montefiore, Charles, with Julia I. Armstrong-Totten. A Dynasty of Dealers: John Smith and Successors 1801-1924. The Roxburghe Club, London, 2013: 53-55.