he armies of the Hellenistic period were quite different from the earlier armies of the eastern Mediterranean. Initially, the formations according to the Macedonian style. Mercenary formations of peltasts and archers were also formed to complement the small detachments of javelinmen and slingers they already had. The cavalry was reorganized into light ( ) and heavy on the model of the Macedonian . The Pontic cities and the Seleucids used mercenary horse archers from the steppe tribes. The Ptolemies and the Seleucids also used war elephants. The Celtic shield was adopted, possibly due to the increased contact, which the Greeks called , and a new type of infantry, the (‘ bearers’), was formed. Armed with spears and javelins, they initially formed a cohesive link between heavy and light formations. Some were equipped with breastplates () and carried out heavy infantry and marine duties.
