Once begun, the new life was extraordinarily energetic on the industrial and constructive side, the independence and rivalry of so many communities securing for the time the maximum of effort. Already in the seventh century, indeed, their industry stood for a new era in history.[522] Where before even the men of the cities had gone clad in skins after the manner of the barbarian conquerors, they now began to weave for themselves woollen cloths like the civilised ancients.[523] Soon the art of weaving the finer cloths, which had hitherto been imported from Greece in so far as they were used at all, followed the simpler craft of wool-weaving.[524] It was in these cities that architecture may be said to have had its first general revival in western Europe since the beginning of the decay of Rome. Walls, towers, ports, quays, canals, municipal palaces, prisons, churches, cathedrals--such were the first outward and visible signs of the new era in Italian civilisation.[525] On these foundations were to follow the literature and the art and science which began the civilisation of modern Europe, the whole presided over and in part ordered and inspired by the recovered use of the great system of ancient Roman law, which too began to be redelivered to Europe early in the twelfth century from Italian Bologna. [The public buildings of the eleventh century are to this day among the greatest in Italy. Cp. Sismondi with Testa, _History of the War of Frederick I against the Communes of Lombardy_, Eng. trans, p. 101. Before the tenth century the houses were mostly of wood, and thatched with straw or shingles (Testa, p. 11). It seems highly probable that the great development of building in the eleventh century was due to the sense of a new lease of life which came upon Christendom when it was found that the world did not come to an end, as had been expected, with the year 1000. That expectation must have gone far to paralyse all activity towards the end of the tenth century.]