Res Gestae
Ammianus Marcellinus
Ammianus Marcellinus. Ammianus Marcellinus, with an English translation, Vols. I-III. Rolfe, John C., translator. Cambridge, MA; London: Harvard University Press; W. Heinemann, 1935-1940 (printing).
And not wishing to leave anything undone that must be done before the heat of battle, he sent men of judgement and offered alternative conditions, urging the defenders of the walls either to give up the possessions of others without bloodshed and return to their own people, or to submit to the sway of Rome and receive increase of honours and rewards. And when with their native resolution they rejected these offers, being men of good birth and inured to perils and hardships, all the preparations for a siege were made.
Then in close array and urged on by the trumpets the soldiers most vigorously attacked the town on every side, and with the legions gathered together into various tortoise-formations[*](See illustration, pp. 328-9.) and so advancing slowly and safely, they tried to undermine the fortifications; but since every sort of weapon was showered upon them as they came up, the connection of the shields was broken and they gave way, while the trumpets sounded the recall.