The gladius was first introduced by the Roman legionaries during the Samnite Wars in the 4th century BCE. It quickly became the standard weapon of the Roman army, and it was used by Roman soldiers for centuries. The gladius was particularly effective against the swords and spears of the Roman Republic's enemies, and it helped the Roman army to conquer much of Europe and the Mediterranean region.
The gladius was eventually replaced by the spatha, a longer and more versatile sword, during the late Roman Empire. However, the gladius remained a popular weapon among Roman soldiers for centuries, and it was even used by some of the Roman emperors. The gladius is still considered to be one of the most iconic weapons of the Roman Empire.