William Mostyn-Owen

William "Willy" Mostyn-Owen (10 May 1929 – 2 May 2011) was a British art historian. He worked for some years with the art expert Bernard Berenson, and was his bibliographer. He was connected with the auctioneers Christie's for 30 years.

Early life William Mostyn-Owen was born on 10 May 1929 to Lt-Col Roger Arthur Mostyn-Owen (1888–1947) and wife Margaret Eva Dewhurst. The Mostyn-Owen family were military landed gentry of Woodhouse, Shropshire. He had three older brothers and a sister. His brothers all died during the Second World War, and his father died while William was in his teens, so that he inherited the family seat of Woodhouse and the Dewhurst family's Aberuchill Castle, Perthshire, at a young age. He was educated at Eton and Magdalene College, Cambridge. In 1968, they were living in a single wing of Aberuchill Castle which consisted of "23 rooms or so".

His second wife was Faith Clark, and his third was Jane Martineau, also an art historian, whom he married in 1992. His son Orlando is an artist and a painter.