 It was used in the Siege of Motya in 397 BC.This was a key Carthaginian stronghold in Sicily, as described in the 1st century AD by Heron of Alexandria in his book "Belopoeica".Other arrow shooting machines such as the larger ballista and smaller "Scorpio" also existed starting from around 338 BC, but these are torsion catapults and not considered crossbows.