Plutarch, Sertorius
Bernadotte Perrin, Ed.

17. But of all his military exploits that which he performed in dealing with the people called Characitani is admired as much as any. They are a people beyond the river Tagonius, and they do not dwell in cities or villages, but on a large and lofty hill containing caves and hollows in the cliffs which look towards the north. The whole country at the base of the hill abounds in white clay and a soil that is porous and crumbly; it is not firm enough to bear the tread of man, and spreads far about if only slightly stirred, like unslaked lime or ashes. [2] These Barbarians, then, whenever they were afraid of war, would hide themselves in their caves, take all their plunder in with them, and keep quiet, for they could not be taken by force; and at the time of which I speak, when Sertorius had retired before Metellus and encamped at the base of their hill, they thought scornfully of him as a vanquished man, and he, either out of anger, or because he did not wish to be thought a fugitive, at break of day rode up to the place and inspected it. [3] There was no attacking it anywhere, but as he was wandering about to no purpose and indulging in empty threats, he saw that dust from the soil which I have described was being carried up against the Barbarians in great quantities by the wind. For the caves, as I have said, faced the north, and the wind which blows from that quarter (some call it Caecias) is the most prevalent and the strongest of the wind in that country, being a confluent of winds from watery plains and snow-covered mountains; and at this time particularly, which was the height of summer, it was strong, was fed by the melting snows of northern regions, and blew most delightfully with continual refreshment for man and beast all day. [4] So, reflecting on these things and getting information about them from the natives of the country, Sertorius ordered his soldiers to take some of the loose and ashy soil that I have described, carry it directly opposite the hill, and make a heap of it there. This the Barbarians conjectured to be a mound raised for assaulting them, and jeered at their enemy. [5] On that day, then, the soldiers of Sertorius worked until night, and were then led back to camp. But when the next day came, at first a gentle breeze arose, stirring up the lightest portions of the gathered soil and scattering them like chaff; then, when Caecias was blowing strong with the mounting of the sun and covering the hills with dust, the soldiers came and stirred up the mound of earth to the bottom and broke up the lumps, while some actually drove their horses back and forth through it, throwing up the loosened earth and giving it to the wind to carry. [6] Then the wind caught up all the earth thus broken and stirred and threw it up against the dwellings of the Barbarians, which opened so as to admit Caecias. And the Barbarians, since their caves had no other inlet for air than that against which the wind was dashing, were quickly blinded, and quickly choked, too, as they tried to inhale an air that was harsh and mingled with great quantities of dust. [7] Therefore, after holding out with difficulty for two days, on the third day they surrendered, thereby adding not so much to the power as to the fame of Sertorius, since by his skill he had subdued what could not be taken by arms.