Unique in its possession of a chained library and of the Mappa Mundi, Hereford Cathedral is remarkable for its architecture, its long history and its musical tradition. Hereford Cathedral is the definitive account of its history from Anglo-Saxon times to the present, and of its architecture, fittings, musical tradition, archives and library. Substantial parts of the structure date from Norman times, but the building has been modified in many ways over the years. In the middle ages Hereford was the centre of pilgrimage to the shrine of St. Thomas Cantilupe, bishop of Hereford (d.1282). It survived the Reformation relatively intact, but was damaged during the Civil War. Its west end collapsed disastrously in 1786, leading to the renewal and reworking of the exterior by James Wyatt. Little was changed in the interior until the striking Victorian rationalisation by George Gilbert Scott.