C. Julius Caesar, Gallic War

Close under the walls of the town, a copious spring gushed out on that part, which for the space of nearly three hundred feet, was not surrounded by the river. While every other person wished that the besieged could be debarred from this spring, Caesar alone saw that it could be effected, though not without great danger. Opposite to it he began to advance the vineae toward the mountain, and to throw up a mound, with great labor and continual skirmishing. For the townsmen ran down from the high ground, and fought without any risk, and wounded several of our men, yet they obstinately pushed on and were not deterred from moving forward the vineae, and from surmounting by their assiduity the difficulties of situation. At the same time they work mines, and move the crates and vineae to the source of the fountain. This was the only work which they could do without danger or suspicion. A mound sixty feet high was raised; on it was erected a turret of ten stories, not with the intention that it should be on a level with the wall (for that could not be effected by any works), but to rise above the top of the spring. When our engines began to play from it upon the paths that led to the fountain, and the townsmen could not go for water without danger, not only the cattle designed for food and the working cattle, but a great number of men also died of thirst.