Calpurnia (kălpûr'nēu) [key], d. after 44 B.C., Roman matron. The daughter of Lucius Calpurnicus Piso Caesoninus (see under Piso, family), she was married to Julius Caesar in 59 B.C. She was loyal to him despite his many infidelities and his neglect. The picture of her in Shakespeare's Julius Caesar is drawn mainly from Plutarch.