The Phalanx was the superior close order battle formation of antiquity until the time of the Romans. Its soldiers wore heavy metallic armor and carried thrusting spears and swords for attacking the enemy at close quarters. While the armor would have been useful in single combat, it became much more lethal in formation.
The origin of the phalanx is not known, but when adopted by the Greeks it became superior to any alternative from the time of Marathon to 197 B.C, when the Greeks were defeated by a Roman javelin and sword army.
Historical evidence suggests that the hoplite armor (chest corslet, helmet, and greaves) developed at about the same time (circa 650 B.C.), and that the phalanx resulted from the armor, not the reverse. The shield predated the other equipment and is of particular importance because the way its use evolved over time.