From the third century BC, the Roman legion added a skirmisher type of soldier to its tactical formation. The Velites were light infantry armed with a short sword (the gladius or pugio), a small round shield, and several small javelins. These javelins were called veruta (singular "verutum"). The Velites typically drew near the enemy, hurled javelins against their formation, and then retreated behind the legion's heavier infantry. The Velites were considered highly effective in turning back war elephants, on account of discharging a hail of javelins at some range and not presenting a "block" that could be trampled on or otherwise smashed – unlike the close-order infantry behind them. At the Battle of Zama in 202 BC, the javelin-throwing Velites proved their worth and were no doubt critical in helping to herd Hannibal's war elephants through the formation to be slaughtered. The Velites would slowly have been either disbanded or re-equipped as more-heavily armed legionaries from the time when Gaius Marius and other Roman generals reorganised the army in the late second and early first centuries BC. Their role would most likely have been taken by irregular auxiliary troops as the Republic expanded overseas. The verutum was a cheaper missile weapon than the pilum. The verutum was a short-range weapon, with a simply made head of soft iron.