Turning to Germany, we find that a very strong resemblance existed between the Romanesque churches of that country and those of North Italy. At Aix-la-Chapelle a polygonal church exists, built by Charlemagne, and which tradition asserts was designed on the model of San Vitale at Ravenna. The resemblance is undoubted, but the German church is by no means an exact copy of Justinian's building. Early examples of German Romanesque exist in the cathedrals of Mayence, Worms, and Spires, and a steady advance was made till a point was reached (in the twelfth century) at which the style may be said to have attained the highest development which Romanesque architecture received in any country of Europe. The arcaded ornament (the arches being very frequently open so as to form a real arcade) which was noticed as occurring in Lombard churches, belongs also to German ones, though the secondary internal arcade (triforium) is absent from some of the early examples. Piers are used more frequently than columns in the interiors, and are often very plain. From an early date the use of a western as well as an eastern apse seems to have been common in Germany, and high western façades extending between two towers were features specially met with in that country. For a notice and some illustrations of the latest and best phase of German Romanesque, which may with propriety be termed "round-arched Gothic," the reader is referred to the companion volume of this series.[34] France exhibits more than one variety of Romanesque; for not only, as remarked in the chapter on Byzantine Art, is the influence of Greek or Venetian artists traceable in the buildings of certain districts, especially Périgueux, but it is clear that in others the existence of fine examples of Roman architecture (Fig. 168) affected the design of buildings down to and during the eleventh century. This influence may, for example, be detected in the use, in the churches at Autun, Valence, and Avignon, of capitals, pilasters, and other features closely resembling classic originals, and in the employment through a great part of Central and Northern France of vaulted roofs. [Illustration: FIG. 168.--VAULTS OF THE EXCAVATED ROMAN BATHS, IN THE MUSÉE DE CLUNY, PARIS.]