During the 9th century, the diocese was devastated by the Vikings. Lichfield itself was unwalled and had become rather poor, so Bishop Peter moved the see to the fortified and wealthier Chester in 1075. His successor, Robert de Limesey, transferred it to Coventry and the diocese was renamed the Diocese of Coventry and Lichfield. At this stage it also covered Derbyshire and most of Warwickshire. In 1539 the see was transferred back to Lichfield and the name was reversed to become the Diocese of Lichfield and Coventry.