[1] In Florence, the British consul commented that Mostyn-Owen was "worth a battleship" for his charm and tact when dealing with American President Harry S. Truman, the King of Norway Haakon VII and other visiting dignitaries.

[1] He joined the auction house Christie's in London, alongside David Carritt, Noel Annesley, and Brian Sewell, and worked there for almost thirty years.

[1] Mostyn-Owen's first wife from 28 September 1960[4] to 1989 was the Italian writer Gaia Servadio, with whom he had three children, Owen (b.

[6] His second wife was Faith Clark, and his third was Jane Martineau, also an art historian, whom he married in 1992.

[1] His daughter Allegra, an art teacher, was the first wife of the politician Boris Johnson.