Polybolos

Ancient Greek siege engine

The polybolos (the name means "multi-thrower" in Greek) was an ancient Greek repeating ballista, reputedly invented by Dionysius of Alexandria (a 3rd-century BC Greek engineer at the Rhodes arsenal,) and used in antiquity. The polybolos was not a crossbow since it used a torsion mechanism, drawing its power from twisted sinew-bundles. However the earlier and similar oxybeles employed a tension crossbow mechanism, before it was abandoned in favor of torsion.

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