In 1067, William the Conqueror assumed control of the Marlborough area and set Roger, Bishop of Salisbury, to building a wooden motte-and-bailey castle, sited on the prehistoric mound. A castle at Marlborough is suggested by the imprisonment and death there of Ethelric, bishop of Selsey, in 1070. William established the neighbouring Savernake Forest as a favourite royal hunting ground, and Marlborough Castle became a royal residence: Henry I spent Easter at Marlborough in 1110, which strongly suggests that it was inhabitable. In 1110, Henry I observed Easter at Marlborough.