Roman Onager

Timeline

1. c. 200–300Roman Empire · Roman EmpireAround the 3rd century the Roman army began adopting more compact single-arm torsion stone-throwers to replace some large ballistae, facilitating rapid deployment on walls and in fortified camps.
2. c. 300–400Roman legionary camps and fortresses · Roman Empire frontiersIn the 4th century the onager became one of the standard items of legionary engineers; historians such as Ammianus recorded its practical use in sieges and defense, hurling stones weighing tens of kilograms.
3. c. 400–500Constantinople · Bosphorus StraitThe Eastern Roman Empire continued to use the onager in city defense, and the technology passed into medieval Europe, becoming one of the important sources of medieval catapult development.