in the military art of the ancients, was a kind of cover or screen which the soldiers formed with their bucklers, by holding them up over their heads, and standing close to each other. This expedient served to shelter them from darts and other missiles, especially those thrown from above, when they went to the assault. The same name was also applied to a large wooden tower which moved on several wheels, and was covered with bullock-hides, serving to shelter the soldiers when they approached the walls to mine them, or to batter them with rams. It was called testudo, from the strength of its roof, which covered the workmen as the shell does the tortoise.