We come across further evidence of their advance at Este,[402] and as they crossed the Po valley they destroyed the _terremare_, which had existed there since early in the bronze age and dispersed their inhabitants.[403] There is evidence that about this time some of the _terramara_-folk arrived in Etruria,[404] others are found settling in the neighbourhood of Taranto,[405] while Dr. Hooton has shown that there are strong reasons for believing that the earliest settlement on the Palatine Hill at Rome was due to these people.[406] The invaders seem to have occupied all the plain of Italy north-east of the Apeninnes, the area known later as Ombrice[407] or Etruria Circumpadana,[408] but the most important spots at which their remains have been found are in and around Bologna. From one of the best-known sites in that city their culture has been called that of Villanova.[409] That at one time they conquered Etruria has been suggested in chapter /IV./, and doubtless it was they who extended the Etruscan rule from the Alps to the south of Naples; but, as has already been explained, it would be a mistake to confuse them with the real Etruscans. [Illustration: FIG. 23.--MAP SHOWING DISTRIBUTION OF TYPE G SWORDS IN FRANCE.] [Illustration: FIG. 24.--MAP SHOWING DISTRIBUTION OF IRON SWORDS IN FRANCE.] We have seen that in the mountain zone the pile-dwelling civilisation continued throughout the bronze age. This type of culture, introduced by the early Alpines from Asia Minor, was adopted in Central Europe by the Nordic intruders, who had made themselves lords over the Alpine peasants. That they were still retaining their race exclusiveness is clear from the fact that long and broad-headed skulls are still found side by side.[410] In the plain, however, where we have no evidence of Alpine settlement, all signs of pile-dwellings are absent. It is a striking fact that with the arrival of iron swords into the mountain zone this pile-dwelling culture, which had existed from early neolithic days till the close of the bronze age, came suddenly to an end. This cannot be merely an accident, for the same thing occurred all over Central Europe.[411] It is also significant that some centuries later it was revived.[412] Some important revolution must have taken place to end so abruptly a custom which had lasted for thousands of years, and to end it with equal suddenness in all parts of the mountain zone. I can only account for it in one way, by supposing that the men of the plain, who had never occupied this type of dwelling, had swept over the mountain zone, carrying fire and the iron sword throughout the villages of their neighbours.