Dr John Cavafy was a physician and collector. He was the son of George John Cavafy, a merchant and partner in G. J. Cavafy and Co, and an important patron of Whistler. At the time of the 1881 census John Cavafy was living at 2 Upper Berkeley Street with his parents, G. J. and Mary Cavafy, and his wife Maria (aged 28) and their daughter Catherine (aged six).
Cavafy was working in St George's Hospital in London in 1886.
Cavafy's father made a number of significant purchases from Whistler in the 1860s, as well as aiding other sales of Whistler's work. The Coast of Brittany y037 was sold by Whistler through G. J. Cavafy to his half-brother G. W. Whistler for £84 in 1863. In 1863, he also bought The Last of Old Westminster y039 for 30 guineas following its exhibition at the Royal Academy in London. In 1863 G. J. Cavafy also bought Battersea Reach y045 for £30. In 1867, he purchased Variations in Flesh Colour and Green: The Balcony y056 for 30 guineas. Harmony in Blue and Silver: Trouville y064 was given to G. J. Cavafy by Whistler at some point before 1878 when Whistler cleaned and restored it, and replaced its frame with a new one designed by himself. Whistler then demanded payment which G. J. Cavafy refused. In a letter to John Cavafy, Whistler suggested that the picture should be returned to the artist, saying 'you have had it quite long enough' (GUW #00549).
John Cavafy frequently acted on behalf of his father in matters of art and business. In 1889 Whistler sought to buy The Last of Old Westminster y039 and Variations in Flesh Colour and Green: The Balcony y056 back for £180. G. J. Cavafy refused. Whistler had borrowed Variations in Flesh Colour and Green: The Balcony y056, and John Cavafy, writing on behalf of his father in March 1889, demanded it back (GUW #00552). He later refused to lend Whistler further works (GUW #00555).
John Cavafy came to own his father's paintings, and sold them (The Last of Old Westminster y039, Battersea Reach y045, Variations in Flesh Colour and Green: The Balcony y056 and Harmony in Blue and Silver: Trouville y064) to the New York dealer E. G. Kennedy for £650 in June 1892. Whistler and John Cavafy were in correspondence from 1878 until 1892.
UK census 1881; Young, Andrew McLaren, Margaret F. MacDonald, Robin Spencer, and Hamish Miles, The Paintings of James McNeill Whistler, New Haven and London, 1980 ; MacDonald, Margaret F., James McNeill Whistler. Drawings, Pastels and Watercolours. A Catalogue Raisonné, New Haven and London, 1995 . The Correspondence of James McNeill Whistler, 1855-1903, edited by Margaret F. MacDonald, Patricia de Montfort and Nigel Thorp; including The Correspondence of Anna McNeill Whistler, 1855-1880, edited by Georgia Toutziari. Online edition, University of Glasgow, 2004.