And what is writ large on these great monuments is written no less unmistakably in the contents of the French museums. That of the world-famous statues of Venus three come from Narbonensis is significant of the taste of Gallic connoisseurs. These great masterpieces were of course imported, but the discoveries at Martres Tolosanes attest the existence of local schools of sculpture.[185] Even if the reliefs of Gallic tombstones in the north and centre diverge somewhat sharply from the Roman convention in preferring the naturalistic to the allegorical in their choice of subject, yet the form is predominantly classical. And the readiness of Gaul to learn the industrial arts of Italy is strikingly proved by its pottery. The manufacture of the red ‘Arretine’ ware or ‘terra sigillata’ was already flourishing among the Ruteni in the first century A.D., and met with such success that it was actually exported to Italy, and finally displaced the home product.[186] In this useful if humble art, Gaul, like Greece, took captive her captor. The causes of this all but complete Romanization are not far to seek. The sword of Caesar was mighty and its argument efficient. Part of this argument the Romans always retained, but as time went on they mingled diplomacy with their militarism. The altar at Lyons had its persuasive side, though the spirit that moved the orator’s tongue was no doubt quickened by the scourge and the river in the background. Yet imperial policy is as clearly seen here as in the utterances of the panegyrists, who are regularly employed to publish the prince’s praises. Caracalla’s extension of the citizenship to provincials is part of the same policy (A.D. 212). Not to exterminate the barbarian tribes, but to bring them within the Empire as cultivators and soldiers, was the aim of the later emperors[187]—an aim which they sometimes followed with ruthless cruelty.[188] Of Constantine the panegyrist says that he entirely cleared Batavia of the Franks who had occupied it, and made them live among Romans, so that they might lose not only their arms but also their savage temper.[189] He brought the barbarous Franks from their original homes in the distant North to till the soil and to fill the armies of the Roman Empire.[190]