Lanfranc's greatest political service to the Conqueror was rendered in 1075, when he detected and foiled the conspiracy which had been formed by the earls of Norfolk and Hereford. Waltheof, 1st Earl of Northumberland, one of the rebels, soon lost heart and confessed the conspiracy to Lanfranc, who urged Earl Roger, the earl of Hereford to return to his allegiance, and finally excommunicated him and his adherents. He interceded for Waltheof’s life and to the last spoke of the earl as an innocent sufferer for the crimes of others; he lived on terms of friendship with Bishop Wulfstan of Worcester.