When the magnitude of the preparations which Cæsar made for his second expedition are considered, it can hardly be doubted that his intentions were to subjugate the whole of Britain. Tacitus, however, in his life of Agricola, confesses that Cæsar, in his two campaigns, only made the discovery of Britain; that, though victorious, he was unable to maintain his position;[435][436] that, on leaving the island, not a single Roman was left behind him; and that, for nearly a hundred years afterwards, the Britons were as free as ever, and paid no tribute to the imperial city.[437] Yet the Romans and ancient Britons were alike gainers by their mutual intercourse; for, from this period, their commercial intercourse rapidly increased. The corn and cattle of the Britons rose to a value hitherto unknown, while iron, and pearls of an inferior description, were eagerly sought after by the Romans. A new and vast field was opened up for their tin, lead, wool, and skins. Their slaves,[438] and dogs, of a remarkable breed, were in great demand; and were readily exchanged for the cut ivory, bridles, gold chains, cups of amber, drinking glasses, and trinkets of various kinds which the Romans exported. A considerable trade also arose between the two countries in lime, marl, and chalk, and in the manufacture of baskets, graceful in design, and curious in workmanship, for which the Britons were famous. [Sidenote: Conquest of Britain, A.D. 43.] [Sidenote: Its state of civilization.] Beyond these facts, however, nothing is known of what passed in Britain between the time when Julius Cæsar left it, and the period when it first became a Roman province under Claudius. When, however, the armies of Claudius landed upon its soil, the Britons had advanced far beyond the painted savages who first exchanged their tin for the trinkets of Phœnicia; and although, in the remote portions of the island, there were still to be found many barbarous tribes, the inhabitants of the coast and of the commercial cities were then scarcely less civilized than they were a thousand years afterwards at the period of the Norman Conquest. London, or Londinium, is described by Tacitus as a place then of considerable trade, though not dignified with the name of a colony, and as the chief residence of the merchants. Clausentum[439] (old Southampton), and Rutupi (Richborough) were commercial ports of some importance, and were occupied by traders who dealt largely with those of Gaul, and extended their business even to Rome itself.