Copied from the Celtiberians with whom the Romans first came in contact during the early stages of their conquest of Hispania, beginning in the 3rd century BC, the gladius, specifically the gladius hispaniensis, became the primary weapon of the Roman legions for the ensuing 500 or so years until it was supplanted by the spatha in the 3rd century AD. The gladius was thus the weapon that gained the Romans their empire, won their greatest victories, pushed their boundaries to their furthest extent, and brought Ancient Rome to the zenith of its power.
There was various versions of the gladius, but all gladii shared the common characteristics of being doubled-edged straight steel swords, with a blade measuring around two feet in length, tapering into a ‘V’ shaped tip and used primarily as a close quarter combat thrusting weapon, although it could be used to cut and slash as well. The handle was typically ridged for the user’s fingers or knobbed for a solid grip, and a significant feature distinguishing the gladius, its successor the spatha, and their immediate descendants into the early and intermediate Middle Ages, was the absence of a crossguard.
It was typically carried in a scabbard affixed to a belt on the legionary’s right hip. In combat, the legionary with his torso armored and his head protected by a helmet carried a long shield, initially oval, later rectangular and curved, that covered most of his body from his shins to his chin. In his right hand, he held his gladius in an underhanded grip, its tip projecting from the right side of his shield at waist level.
The legionary strove to stab his gladius into his foe’s abdomen or chest; above the upper rim of his shield into the enemy’s face or neck; or if the opportunity presented itself, slashing at the opponent’s knees or legs, or hamstringing him with a drawing cut. The gladius’ relatively short blade was an advantage in close quarters because it allowed the legionary to step inside his enemy’s guard and thrust at speed in any direction from which his foe was vulnerable – a task that would be awkward with a long sword, which would have required more space between the parties for optimal thrusting.