The army of Theban polis in the 4th century BC was primarily the work of two outstanding reformers and commanders - Epaminondos (even Plutarch writes about him in one of his "Lives of famous men) and Pelopidas. The Theban army, as a result of the reforms carried out by these two commanders, still saw hoplites as the main fighting force, but with much lighter weapons than in the 5th century BC, with slightly longer spears, although still carrying hoplons. Light infantry, especially peltasts, were also used on a large scale in the Theban army. There was also an elite unit called the Holy Host, consisting of 300 soldiers, probably having sexual relations with each other. Great changes took place in the battle order, because Epaminondosa consciously strove to strengthen one of the wings during the battle and put it forward in front of the rest of his army, creating a de facto oblique formation. The army changed in this way brought Thebes great successes in the battles of Reading (371 BC) and Mantinea (362 BC). It is worth adding that many novelties introduced in the Theban army were later successfully used by Philip II of Macedon and Alexander the Great.
The Greek phalanx was probably created in the 8th or 7th century BC. It was a combat formation of heavy-armed infantry, formed by hoplites who lined up to fight in ranks, the number of which during the Greco-Persian Wars (500 / 499-449 BC) ranged from 8 to 16. The phalanx was a closed (closed) ), in which soldiers covered each other with shields. It primarily assumed the use of melee weapons (a spear or a sword) and marginalized, especially at the beginning, the use of a throwing weapon. In the 5th century BC the hoplite was armed with a wooden bronze shield (Greek hoplon - hence the name of a soldier fighting in a phalanx), on his head he had a bronze helmet (often of the Corinthian type) and the so-called athlete's armor also made of bronze. However, there were also canvas armor. Back then, hoplite legs were almost always protected with greaves. The offensive armament was mainly a spear and a short single-edged sword (Greek: machaira) or double-edged sword (Greek: xiphos). The phalanx provided the Greek polis with a huge military advantage over the troops of the Persian Empire during the wars of 500 / 499-449 BCE, and was also used later, e.g. during the Peloponnesian War (431-404 BCE), when however, it began to undergo an evolution, as a result of, for example, Iphicrates' reforms in Athens. It is commonly assumed that in the 5th century BC, Sparta had the best army among the Greek polis, whose hoplites moved to the battlefield most often with the Greek letter lambda painted on the hoplon - from Lakedemon, another name for their homeland. Based on the foundations of the Greek phalanx in the 4th century BC, Philip II of Macedon and Alexander the Great introduced the Macedonian phalanx to the battlefields.