In 667 Saint Aubert, bishop of Cambrai, decided to found the Abbey of Saint Vaast, which developed during the Carolingian period into an immensely wealthy Benedictine abbey. The modern town of Arras initially spread around the abbey as a grain market. During the 9th century, both town and abbey suffered from the attacks of the Vikings, who later settled to the west in Normandy. The abbey revived its strength in the 11th century and played an important role in the development of medieval painting, successfully synthesizing the artistic styles of Carolingian, Ottonian and English art.