 Sir John Radcliffe, baptized on 31 December 1539 at the church of St Lawrence Pountney in London, was the younger but only surviving son of Robert Radcliffe, 1st Earl of Sussex, and his third wife, Mary Arundell.By his father's two earlier marriages he had three brothers and two sisters of the half blood.Sir John Radcliffe's father, Robert Radcliffe, 1st Earl of Sussex, married firstly, shortly after 23 July 1505, Elizabeth Stafford, the elder daughter of Henry Stafford, 2nd Duke of Buckingham, and Katherine Woodville, by whom he had three sons