The art and architecture of the reign of Charlemagne (800–814), the first Holy Roman emperor, and of his successors until about 900. Charlemagne's reign was noteworthy for reforms in many fields: his guiding principle was a renewal of the values of the Roman empire, and this was felt in the arts no less than in administrative, judicial, and religious matters. His capital was at Aachen (Aix-la-Chapelle), which became the centre of a cultural revival following a bleak period for the arts in the Franco-German lands that formed the heart of his vast empire. Charlemagne recognized the value of the arts for the education of his subjects and was himself the principal initiator of the cultural revival. Little survives of Carolingian mural paintings or mosaics, but several manuscripts contemporary with Charlemagne are known, showing a classical, naturalistic figure style, but also at times a vivid expressiveness. There was no large-scale sculpture, but Carolingian ivory sculpture and metalwork (on book covers, for example) often reached a high level. Carolingian art had great influence on Ottonian and Romanesque art.