John Roydon Peacock was the son of Ralph Peacock, an accomplished portrait painter whose work is represented by two paintings in the Tate Gallery and others in various national galleries throughout the world. He studied at Cambridge where he graduated with first class honours in the Natural Science

John Foster, the eldest son of John Robert Foster, an ophthalmic surgeon, and of Emily Jane (née Elliot) was born on 31 October 1903 in West Hartlepool. He was educated at Aysgarth School, Uppingham School and Caius College, Cambridge, before entering the London Hospital Medical School where he won