Caen (1120). The wide adoption of this method led to the development of Gothic architecture. Several churches of Aquitaine and Anjou are roofed with domes, and have no aisles, as at Angouleme Cathedral. Notable examples Abbey Church of Cluny, Cluny, Bourgogne-Franche-Comté The Abbey of Saint-Etienne, Caen, Normandy The Church of the Abbey of la Trinité, Caen, Normandy The Basilica of St. Sernin, Toulouse, Occitania Angoulême Cathedral, Angoulême, Nouvelle-Aquitaine Saint-Front, Périgueux, Nouvelle-Aquitaine Notre Dame du Puy, Le Puy-en-Velay, Auvergne-Rhône-Alpes Abbey Church of Saint-Savin-sur-Gartempe, Saint-Savin-sur-Gartempe, Nouvelle-Aquitaine Abbey of la Madaleine, Vézelay, Bourgogne-Franche-Comté Church of St Philibert, Tournus, Bourgogne-Franche-Comté Abbey of Saint-Pierre, Moissac, Occitania Abbey of Saint-Georges, Saint-Martin-de-Boscherville, Normandy Romanesque churches in Britain and Ireland Influences The Pre-Romanesque tradition of architecture was Saxon. The thick-walled churches without aisles had archway leading into rectangular chancels. Bell towers often had an attached circular stair turret. Windows were often arched or had triangular heads. The Norman invasion of 1066 unified the government of England. Norman bishops were installed in English cathedrals and monasteries were established following Benedictine, Cluniac, Cistercian, and Augustinian rules. Monasteries were established in Wales, Scotland and Ireland, suppressing local Celtic monastic tradition. Many cathedrals were of monastic foundation serving a dual role, which affected their architecture, in particular the extended length of the choir and transepts. There was a great diversity of building stone including limestone, New Red Sandstone, flint and granite. In England, the relative political stability led to large diocese with few bishops. Cathedrals were correspondingly few in number and large in scale. Geographical isolation led to the development of distinct regional character. The climate led to the construction of long naves to facilitate processions in wet weather. Of the medieval cathedrals, nearly all were commenced in this period, and several have remained substantially Norman structures. Many parish churches were commenced at this period. The abbey churches suffered destruction at the time of the dissolution of the monasteries in the early 16th century and the majority were reduced to ruins, some surviving as parish churches. Characteristics It is characteristic of the medieval churches of the British Isles and England in particular that they were continually expanded, altered and rebuilt. Consequently, although Norman buildings are numerous, few are intact, and at some, such as Lincoln Cathedral, Gloucester Cathedral and Worcester Cathedral, Norman architecture might be represented only by the portals, the columns of the nave or the crypt. The Norman facades of