XIII.  Besides this, Metellus was now growing old, and after so many great battles was somewhat inclined to an easy and luxurious mode of life; and he was opposed to Sertorius, a man full of the vigour of mature age, whose body was wonderfully furnished with strength, activity, and power of endurance.  He was never intoxicated with drink, even in his seasons of relaxation, and he was accustomed to bear great toil, long marches, and continued watchfulness, content with a little food of the meanest quality; and, inasmuch as he was always rambling about and hunting, when he had leisure, he became intimately acquainted with all the spots, both impracticable and practicable, which gave chance of escape if he had to fly, or opportunity of hemming in an enemy if he was in pursuit.  Consequently, it happened that Metellus, being prevented from fighting, was damaged as much as men who are beaten in battle, and Sertorius by flying had all the advantage of the pursuer.  He used to cut off the supplies of water, and check the foraging; and when Metellus was advancing Sertorius would get out of his way, and when he was encamped he would not let him rest; when Metellus was occupied with a siege, Sertorius would all at once show himself, and put Metellus in his turn in a state of blockade, owing to the want of the necessary supplies, so that the soldiers were quite wearied; and when Sertorius challenged Metellus to a single combat, the men cried out and bid him fight, as it would be a match between a general and a general, and a Roman and a Roman; and when Metellus declined, they jeered him.  But he laughed at them, and he did right; for a general, as Theophrastus[141] said, should die the death of a general, not that of a common targetier.  Metellus perceiving that the Langobritae[142] assisted Sertorius in no small degree, and that their town could easily be taken, as it was ill supplied with water, for they had only one well in the city, and any one who blockaded the place would be master of the streams in the suburbs and near the walls, he advanced against the city, expecting to finish the siege in two days, as there was no water; and accordingly his soldiers received orders to take provisions with them for five days only.  But Sertorius quickly coming to their aid, gave orders to fill two thousand skins with water, and he offered for each skin a considerable sum of money.  Many Iberians and Moors volunteered for the service, and, selecting the men who were strong and light-footed, he sent them through the mountain parts, with orders, when they had delivered the skins to the people in the city, to bring out of the town all the useless people, that the water might last the longer for those who defended the place.  When the news reached Metellus he was much annoyed, for his soldiers had already consumed their provisions; but he sent Aquinius,[143] at the head of six thousand men, to forage.  Sertorius got notice of this, and laid an ambush on the road of three thousand men who starting up out of a bushy ravine, fell on Aquinius as he was returning.  Sertorius attacked in front and put the Romans to flight, killing some and taking others prisoners.  Aquinius returned with the loss of both his armour and horse, and Metellus made a disgraceful retreat amidst the jeers of the Iberians.