Antonius himself was this way inclined, and he ordered the entrenched camp to be invested. At first they fought from a distance with arrows and stones, the Flavianists suffering most, as the enemy's missiles were aimed at them from a superior height. Antonius then assigned to each legion the attack on some portion of the entrenchments, and on one particular gate, seeking by this division of labour to distinguish the cowardly from the brave, and to stimulate his men by an honourable rivalry. The 3rd and 7th legions took up a position close to the road from Bedriacum; more to the right of the entrenchments were stationed the 8th and the 7th (Claudius'). The 13th were carried by the impetuosity of their attack as far as the gate looking towards Brixia. There ensued a little delay, while from the neighbouring fields some were collecting spades and pick-axes, others hooks and ladders. Then raising their shields over their heads, they advanced to the rampart in a dense "testudo." Both used the arts of Roman warfare; the Vitellianists rolled down ponderous stones, and drove spears and long poles into the broken and tottering "testudo," till the dense array of shields was loosened, and the ground was strewn with a vast number of lifeless and mangled bodies.
Complete Works of Tacitus. Tacitus. Alfred John Church. William Jackson Brodribb. Sara Bryant. edited for Perseus. New York. : Random House, Inc. Random House, Inc. 1873. reprinted 1942.
