The next theory, which for a long time has had its supporters, makes Marius the hero whose triumph it celebrates; and they point to the name of Marius carved on one of the shields of the monument in support of their contention. Julius Cæsar has been suggested as the possible builder, and so has Octavius; but the general opinion held to-day is that it was erected during the reign of Tiberius to commemorate his overthrow of Julius Sacrovir, who tried to incite the Gauls to rebel against Rome A.D. 21. This theory has been supported by the discovery of the marks of nails which held in position the bronze letters of an inscription removed by Raymond de Baux when he transformed the arch into a fortress in the thirteenth century. These marks have been supposed to correspond with the first letters of the name of Tiberius; but whatever the victory may have been that the triumphal arch commemorates, its presence in Orange is one of many proofs of the importance of the ancient city of Arausio. The ramparts and towers that surrounded the Roman town have all disappeared. Visigoth and Teuton broke down the power of the Empire, demolishing its works on every hand. The Saracens in turn possessed the town, and fierce battles raged around it before Charlemagne drove them out. In the Middle Ages it was subjected to the continued strife and warfare of contending feudal factions, but the Arch and the Theatre remain to speak of its former greatness. At the opposite side of the town from where the Lyons [Illustration: THEATRE. AT ORANGE] road enters it, a great hill rises from the plain, and on its crest the castle of the Princes of Orange stood in former days. At the foot of the hill, on its townward side, stands a huge wall, some 340 feet long, 120 feet high, and 13 feet in thickness. One can only stand awestruck in front of this gigantic structure that overshadows and dwarfs the town. No wonder that Louis XIV. called it the finest wall in all his wide kingdom. It awakens emotions akin to those one feels on beholding “The Pyramids” of Egypt, or its nearer neighbour the “Pont du Gard.” This wall forms the back of the proscenium of the Roman theatre, and is the most unique specimen in existence. The great façade, with its projecting corbels which supported tall masts, its rows of blind and open arches, even though damaged, much worn, and shorn of its carvings, has a noble grandeur due mainly to its size. Originally there was a forecourt, bounded at either end by two projecting structures, which gave a greater architectural beauty to the pile. The Theatre, although so purely Roman, is built at the foot of the hill which is used for the cavea, a practice that was adopted invariably by the Greeks and seldom by the Romans.