Hoplites were citizen-soldiers of Ancient Greek city-states who were primarily armed with spears and shields. Hoplite soldiers utilized the phalanx formation in order to be effective in war with fewer soldiers. The hoplites were primarily represented by free citizens—propertied farmers and artisans—who were able to afford the bronze armour suit and weapons (estimated at a third to a half of its able-bodied adult male population). Hoplites were not professional soldiers and often lacked sufficient military training. Although some states did maintain a small elite professional unit, hoplite soldiers were relied on heavily and made up the bulk of ancient Greek armies of the time.
In the 8th or 7th century BC, Greek armies adopted a military innovation known as the phalanx formation. The formation proved successful in defeating the Persians when employed by the Athenians at the Battle of Marathon in 490 BC during the First Greco-Persian War. The Persian archers and light troops who fought in the Battle of Marathon failed, because their bows were too weak for their arrows to penetrate the wall of Greek shields that made up the phalanx formation. The phalanx was also successfully employed by the Greeks at the Battle of Thermopylae in 480 BC and at the Battle of Plataea in 479 BC during the Second Greco-Persian War.
The word hoplite (Greek: ὁπλίτης hoplitēs; pl. ὁπλῖται hoplitai) derives from hoplon (ὅπλον, plural hopla ὅπλα), the name for the type of shield used by the soldiers. However, the shield was more commonly known as an aspis, so the word hopla may refer to the soldiers' weapons or even their full armament. In the modern Hellenic Army, the word hoplite (Greek: oπλίτης) is used to refer to an infantryman.