Detailed diagrams of Zopyros’s heavy gastraphetes (γαστραφέτης) by E. W. Marsden: general plan, side-elevation, front-elevation. The gastraphetes was an ancient Hellenic invention that nowadays is usually described as a crossbow. But actually, unlike the Roman and medieval European crossbow which

was spanning as a weapon by pulling up the string, the gastraphetes was spanning by pushing down an elaborate slider mechanism. The gastraphetes was a hand-held weapon.

Zopyros was a Tarentine Greek engineer who invented the aforementioned heavier and static type of gastraphetes.

Below, a modern reconstruction of the original, light hand-held gastraphetes for comparison to Zopyros’s heavy version (Wikimedia commons).