Editing Ballista (section)

=== Ballistae in the Roman Empire ===
During the conquest of the Empire, the ballista proved its worth many times in sieges and battles, both at sea and on land. It is from the time of the Roman Empire that many of the archaeological finds of ballistae date. Accounts by the finders, including technical manuals and journals, are used today by archaeologists to reconstruct these weapons.

After Julius Caesar, the ballista was a permanent fixture in the Roman army and, over time, modifications and improvements were made by successive engineers. This included replacing the remaining wooden parts of the machine with metal, creating a much smaller, lighter and more powerful machine than the wooden version, which required less maintenance (though the vital torsion springs were still vulnerable to the strain). The largest ballistae of the 4th century could throw a dart further than 1200 yards (1,100 m). The weapon was named ''ballista fulminalis'' in ''[[De rebus bellicis]]'': "From this ballista, darts were projected not only in great number but also at a large size over a considerable distance, such as across the width of the Danube River."<ref>De Rebus Bellicis, Chapter XVIII: ballista fulminalis. Note: The modern width of the Danube is 1.5 km. During the Roman Empire, it was unlikely to have been less than 1.1 km, bearing in mind that [[Trajan's Bridge]] is known to have been longer than 1.1 km.</ref> Ballistae were not only used in laying siege: after AD&nbsp;350, at least 22 [[bastion|semi-circular towers]] were erected around [[London Wall|the walls]] of [[Londinium]] ([[City of London|London]]) to provide platforms for permanently mounted defensive devices.<ref>{{cite web|url=http://archive.museumoflondon.org.uk/Londinium/Today/vizrom/01+wall.htm |title=Visible Roman London: City wall and gates |publisher=Museum of London Group |access-date=19 February 2015 |url-status = dead|archive-url=https://web.archive.org/web/20150219043325/http://archive.museumoflondon.org.uk/Londinium/Today/vizrom/01%2Bwall.htm |archive-date=19 February 2015 |df=dmy }}</ref>