A combination of protection and mobility make Peltastai suitable for skirmishing duties as well as for taking a stand as part of the main battle line.
The Peltastai is a type of elite skirmisher that sacrifices heavy arms and armor for mobility and range. They are armored in linen and carry a medium sized ovular shield. Originally, they carried a crescent shaped ‘pelta’ shield, originated in Thrake which gave the Peltastai their name, but this was phased out in the fourth century. Their armaments consist of several javelins and a sword. This panoply makes them light and mobile, but still able to engage in melee after their javelins have been thrown. They are a versatile unit but one must remember that their primary arms are javelins, and they are not equipped to stand toe to toe with heavier infantry. Their role is one of speed, harassment, and critical flanking manoeuvres.
Historically, the Peltastai were often Hoplitai or Pezhetairoi equipped to fight in the manner of a skirmisher. This meant that they were adept melee combatants as well as being deadly with their javelins. Peltastai were used to great effect on ancient battlefields but by 270 BC the Thureophoros was becoming the dominant melee skirmisher and the Peltastai were carrying more javelins and were used in a manner that was consistent with this. This was simply a matter of specialization, and it did not mean that Peltastai would be any less effective if deployed correctly. Their light armament makes them extremely fast, but tends to be to their detriment in melee combat. They were mostly used in the role of supporting missile troops who charged in at the last moment, after they had spent all their javelins. The great Athenian general Iphikrates is credited with the invention of the peltast as a distinct unit, and it is he that first employed them in this manner to great effect against the heavier armored and better trained Hoplitai of Sparte.