Cæsar, emulating and surpassing Marius in his campaigning zeal, conquered all Gaul, and under him the first Roman colonies took a firm hold upon the fertile regions in the valley of the Rhone. Arles became a maritime town, which rivalled Marseilles itself. The Celtic inhabitants, mixed strongly with the Phœnician element, were possessed of arts and crafts almost as highly developed as those of the conquering Romans. The city grew in importance until its population numbered 100,000. Traders from all parts of the world flocked to its markets, everything being brought to the city either by river-boats up and down the Rhone, or across the lagoons on rafts, or overland on the backs of mules and horses. The city could offer to its citizens every luxury known to the age. [Illustration: THE ARENA AT ARLES.] The great amphitheatre, built or commenced during the reign of Claudius Tiberius Nero, at the time when the power of Rome was at its zenith, could accommodate nearly 27,000 spectators to witness the wild beast and gladiatorial shows so popular in Rome at that period. It was constructed in the early days of amphitheatres, and is perhaps one of the oldest extant, and gives, together with the Arena at Nîmes, a more vivid impression of the Empire’s strength and grandeur than any other Roman monument in France. Although on a much smaller scale than the mighty Coliseum at Rome (which was built at a much later date and replaced earlier buildings in that city, could accommodate 100,000 spectators, and was over 615 feet in length and 510 feet in width, as compared with the Arena at Arles, 450 feet long and 351 feet wide), it gives some notion of the important part the amphitheatre played in the life of the Roman capital. The amphitheatre at Arles, unlike that of Nîmes, was, if the evidence of the height of the wall of the Podium enclosing the Arena is trustworthy, used for the great fights of lions, tigers, elephants, and other animals, as well as for combats between the gladiators--elaborate and extravagant spectacles that riveted the attention and ministered to the enjoyment of the Roman world for a period extending over seven hundred years. The immense arenas at Arles and Nîmes are proof of the prosperity of these two colonies. Many of the Greek traditions of the Arlesiens were lost sight of and contemned by the [Illustration: ARCHES OF THE ARENA. NIMES.] conquerors, but the refined and intellectual amusements of the Greeks made a slight appeal to the tastes of the warrior race, who overthrew them, and who built a theatre in Arles, in the first century, under the strong influence of the Greek element in the colony, an influence that had made itself felt also in the architecture of the Arena.