A battering ram is a weapon used from ancient times. It is essentially a very heavy weight on wheels, designed to break open fortification walls or doors. It was a step forward from a simple log ram, although it was also made out of a tree trunk. A log ram was simply carried by a group of men, a battering ram was slung from a wheeled support frame via ropes so that it could be much more massive and also more easily swung against its target, sometimes the ram would be reinforced with metal bands and the attacking point could also be metal-bound. Many battering rams had protective roofs and side-screens covered in leather and/or other materials to prevent the ram being set on fire.

In castles, defenders attempted to foil battering rams by dropping obstacles in front of the ram just before it hit a wall, using grappling hooks to immobilize the log, setting the ram on fire, or sallying to attack the ram.

Variations on the battering ram included the drill, the mouse, and the pick. These were smaller than a ram and could be used in more limited spaces.

Battering rams are still used in various roles in modern times, sometimes mounted on vehicles. SWAT teams often use small two-man metal rams for opening locked doors.

Legendary battering ram usage:

• Destruction of Jerusalem
• Used throughout the Crusades
• The fall of Rome

There exists a popular myth in Gloucester that the famous children's rhyme, Humpty Dumpty, is about a battering ram used in the siege of Gloucester in 1643, during the English Civil War. However the story is almost certainly untrue; during the siege, which lasted only one month, no battering rams were used, although numbers of cannon were. The idea seems to have originated in a spoof history essay by Professor David Daube written for The Oxford Magazine in 1956, which was widely believed despite obvious improbabilities (e.g. planning to cross River Severn by running the ram down a hill at speed, although the river is naturally about 100 feet (30 m) wide at this point).