5. But in winter, the ground being covered over with a smooth crust of ice, and therefore slippery under foot, the traveller is often plunged headlong; and the valleys, which seem to open here and there into wide plains, which are merely a covering of treacherous ice, sometimes swallow up those who try to pass over them. On account of which danger those who are acquainted with the country fix projecting wooden piles over the safest spots, in order that a series of them may conduct the traveller unhurt to his destination; though if these piles get covered with snow and hidden, or thrown down by melting torrents descending from the mountains, then it is difficult for any one to pass, even if natives of the district lead the way. 6. But on the summit of this Italian mountain there is a plain, seven miles in extent, reaching as far as the station known by the name of Mars; and after that comes another ridge, still more steep, and scarcely possible to be climbed, which stretches on to the summit of Mons Matrona, named so from an event which happened to a noble lady. 7. From this point a path, steep indeed, but easily passable, leads to the fortress of Virgantia.[51] The sepulchre of this petty prince whom we have spoken of as the maker of these roads is at Susa, close to the walls; and his remains are honoured with religious veneration for two reasons: first of all, because he governed his people with equitable moderation; and secondly, because, by becoming an ally of the Roman republic, he procured lasting tranquillity for his subjects. 8. And although this road which I have been speaking of runs through the centre of the district, and is shorter and more frequented now than any other, yet other roads also were made at much earlier periods, on different occasions. 9. The first of them, near the maritime alps, was made by the Theban Hercules, when he was proceeding in a leisurely manner to destroy Geryon and Tauriscus, as has already been mentioned; and he it was who gave to these alps the name of the Grecian Alps.[52] In the same way he consecrated the citadel and port of Monæcus to keep alive the recollection of his name for ever. And this was the reason why, many ages afterwards, those alps were called the Penine Alps.[53]