Late Roman artillery at the Saxon shore.
The legionaries were well equipped with artillery: a figure of around 60 machines per legion is found in both Josephus (Jewish War 3.166) and Vegetius (2.25). The machines were of various sizes: Trajan’s Column shows both man-portable boltthrowers (manuballistae, cheiroballistrae) and those mounted on a mule-drawn carriage (carroballistae) (Scenes 65-66). Range and accuracy were impressive: at Hod Hill in Dorset, a hill-fort probably captured by Legio II Augusta in ad 43, 17 bolt-heads have been found, still embedded in the chalk where they struck. Eleven had hit Hut 37 (dubbed by archaeologists the “Chieftan’s Hut”), landing in a ten-meter circle, including four that landed in a three-meter circle, all from an estimated range of 170 meters. Of the six other shots it is likely that some at least were initial ranging shots, from which the firers corrected their aim. A reconstructed cheiroballistra has achieved similar results. Although crucial in sieges and assaults, artillery was used in field battles too: at Cremona in ad 69, an “enormous ballista,” of the Fifteenth Legion threw “huge” stones at the Flavian army; only by disguising themselves with the shields of fallen Vitellian troops did two bold individuals put it out of action, by cutting the twisted cord springs which provided its torsion (Tacitus, Hist. 3.25) – a key vulnerability of such machines.