Battle of Gaugamela main Persian infantry was poorly trained and equipped in comparison to Alexander's pezhetairoi and hoplites. The only respectable infantry Darius had were his 2,000 Greek hoplites and his personal bodyguard, the 10,000 Immortals. The Greek mercenaries fought in a phalanx, armed not with a heavy shield but with spears no longer than three metres, while the spears of the Immortals were two metres long. Among the other Persian troops, the most heavily armed were the Armenians, who were armed the Greek way and probably fought as a phalanx. The rest of Darius' contingents were much more lightly armed; the main
Spartan army peltasts became a much more common sight on the Greek battlefield and themselves became more heavily armed. In response to Iphicrates' victory over Sparta in 392 BC, Spartan hoplites started abandoning body armour and eventually wore almost no armour apart from a shield, leg greaves, bracelets, helmet and a robe. In later periods Spartans did start to readopt armour, but on a much lesser scale than during the Archaic period. Finally during 227 BC, Cleomenes' reforms introduced updated equipment to Sparta, including the Macedonian "sarissa" (pike). However pike-men armed with the "sarissa" never outnumbered troops equipped in the hoplite style.