Background
Fortescue, born in London in or about 1578, was the only son of John Fortescue, by Ellen, daughter of Ralph Henslow of Barrald, Kent. His father was the second son of Sir Anthony Fortescue (third son of Adrian), by Katharine, daughter of Sir Geoffrey Pole. His father resided for many years in London, but in his old age he retired to Saint Omer to avoid persecution as a Catholic.