Marchmain family, fictional upper-class Roman Catholic English family featured in the novel Brideshead Revisited (1945) by Evelyn Waugh. The family consists of Lord Marchmain, who lives in Italy with his mistress, Cara; Lady Marchmain, a devout Roman Catholic who lives at the country estate of Brideshead; and their children, Brideshead (Bridey), Sebastian, Julia, and Cordelia.