The pezhetairoi (πεζέταιροι, singular: pezhetairos) were the backbone of the Macedonian army and Diadochi kingdoms. They were literally "foot companions" (in Greek, pezos means "foot warrior" or "infantryman", and hetairos means "companion" or "friend").
Macedonian phalanx wielding the sarissa - a 4 to 7 meter feet) long spear. The invention of the sarissa is credited to Philip II, father of Alexander the Great. This creative thinking helped Alex win battles.