Within a few dozen years the Roman eagles were masters of Britain as far as the Highlands: the Keltic clan-life and the religion of the Druids withdrew into the Caledonian mountains, and the large islands off that coast; in the conquered territory the religion of the arms that had won the victory, and the might of the Great Empire, were supreme. The work which was begun by superiority in war was completed by pre-eminence in civilisation. It seemed an advantage and an improvement to the sons of the British princes, to adopt the Roman language, and knowledge, and mode of life; they delighted in the luxury of colonnades, baths, feasts, and city life. Men like Agricola used these modes of Romanising Britain by preference. Just as the Britons exchanged their rude shipbuilding and their leathern sails for the discoveries of a more advanced art of navigation, so they learnt to carry on their agriculture in Roman fashion; in later times Britain was considered as the granary of the legions in Germany. Most of the cities in the land betray by their very names their Roman origin; London, though it existed earlier, owes its importance to this connexion. It was the emporium destined as it were by nature for the peaceful commerce that now arose between the Western provinces of the Empire. Once in the third century an attempt was made to make the island independent, but it failed the moment the marts on the opposite coast fell into the hands of the Emperor who was universally recognised. Britain seemed an integral part of the Roman Empire. It was from York that Constantine marched forth to unite its Eastern and Western halves once more under one government. But soon after him an epoch began in which the third great nationality, at first thought to be part of the Keltic race, then driven back or taken into service by the Romans, but always maintaining its peculiar original independence--the German, rose to supremacy in the West. In the fifth century it had become everywhere master in the militarily-organised Roman frontier districts: encouraged by the embarrassments of the authorities it advanced into the peaceful provinces. It is of importance to remark what the fate of Britain was in these struggles. From the Romanised territory an Augustus, called Constantine, set up by the revolted legions, invaded Gaul, not merely to check the inroads of the barbarians, but at the same time to possess himself of the Empire. He at one time held a great position, when the legions of Gaul and Aquitaine also took his side, and Spain saluted him Emperor. But the authority of Honorius the generally recognised Emperor could not be so easily set aside: discontented followers of the new Augustus again went over to the old one: before them and the barbarians combined Constantine fell, and soon after paid for his attempt with his life.