Light infantry in the context of "Infantry"

Hoplites (/ˈhɒplaɪts/ HOP-lytes) (Ancient Greek: ὁπλῖται, romanized: hoplîtai [hoplîːtai̯]) were citizen-soldiers of Ancient Greek city-states who were primarily armed with spears and shields. Hoplite soldiers used the phalanx formation to be effective in war with fewer soldiers. The formation discouraged the soldiers from acting alone, for this would compromise the formation and minimize its strengths. The hoplites were primarily represented by free citizens – propertied farmers and artisans – who were able to afford a linen or bronze armour suit and weapons (estimated at a third to a half of its able-bodied adult male population). Some states maintained a small elite professional unit, known as the epilektoi or logades ('the chosen') because they were picked from the regular citizen infantry. These existed at times in Athens, Sparta, Argos, Thebes, and Syracuse, among other places. Hoplite soldiers made up the bulk of ancient Greek armies.

In the 8th century BC, Greek armies started to adopt 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 of the phalanx formation. The phalanx was also 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.

Combat arms (or fighting arms in non-American parlance) are troops within national armed forces who participate in direct tactical ground combat. In general, they are units that carry or employ weapons, such as infantry, cavalry, and artillery units. The use of multiple combat arms in mutually supporting ways is known as combined arms. In some armies, notably the British Army and Canadian Army, artillery and combat engineer units are categorized as combat support, while in others, such as the U.S. Army, they are considered part of the combat arms. Armored troops constitute a combat arm in name, although many have histories derived from cavalry units.

Artillery is included as a combat arm primarily based on the history of employing cannons in close combat, and later in the anti-tank role until the advent of anti-tank guided missiles. The inclusion of special forces in some armed forces as a separate combat arm is often doctrinal because the troops of special forces units are essentially specialized infantry, often with historical links to ordinary light infantry units.

The spatha was a type of straight and long sword, measuring between 0.5 and 1 metre (20 and 40 inches), with a handle length of between 18 and 20 centimetres (7 and 8 inches), in use in the territory of the Roman Empire during the 1st to 6th centuries AD. Later swords, from the 7th to 10th centuries, like the Viking swords, are recognizable derivatives and sometimes subsumed under the term spatha.

The Roman spatha was used in war and in gladiatorial fights. The spatha of literature appears in the Roman Empire in the 1st century AD as a weapon used by presumably Celtic auxiliaries and gradually became a standard heavy infantry weapon by the 3rd century AD, relegating the gladius to use as a light infantry weapon. The spatha apparently replaced the gladius in the front ranks, giving the infantry more reach when thrusting. While the infantry version had a long point, versions carried by the cavalry had a rounded tip that prevented accidental stabbing of the cavalryman's own foot or horse.

The Battle of the Trebia (or Trebbia) was the first major battle of the Second Punic War, fought between the Carthaginian forces of Hannibal and a Roman army under Sempronius Longus on 22 or 23 December 218 BC. Each army had a strength of about 40,000 men; the Carthaginians were stronger in cavalry, the Romans in infantry. The battle took place on the flood plain of the west bank of the lower Trebia River, not far from the settlement of Placentia (modern Piacenza), and resulted in a heavy defeat for the Romans.

War broke out between Carthage and Rome in 218 BC. The leading Carthaginian general, Hannibal, responded by leading a large army out of Iberia (modern Spain and Portugal), through Gaul, across the Alps and into Cisalpine Gaul (in northern Italy). The Romans went on the attack against the reduced force which had survived the rigours of the march, and Publius Scipio personally led the cavalry and light infantry of the army he commanded against the Carthaginian cavalry at the Battle of Ticinus. The Romans were soundly beaten and Scipio was wounded. The Romans retreated to near Placentia, fortified their camp and awaited reinforcement. The Roman army in Sicily under Sempronius was redeployed to the north and joined with Scipio's force. After a day of heavy skirmishing in which the Romans gained the upper hand, Sempronius was eager for a battle.

Count Pyotr Alexandrovich Rumyantsev-Zadunaisky (Russian: Пётр Алекса́ндрович Румя́нцев-Задуна́йский; 15 January [O.S. 4 January] 1725 – 19 December [O.S. 8 December] 1796) was one of the foremost Russian military commanders of the 18th century, widely considered to be one of Russia's greatest military leaders and is referred to as one of the greatest commanders in military history. As a commander, he is placed on par with Alexander Suvorov. Rumyantsev used mobile divisional squares for the first time in history as opposed to linear battle orders and initiated the formation of light (jaeger) battalions in the Russian Army, which operated in a scattered order.

He governed Little Russia in the name of Empress Catherine the Great from the abolition of the Cossack Hetmanate in 1764 until Catherine's death 32 years later. Monuments to his victories include the Kagul Obelisk in Tsarskoye Selo (1772), the Rumyantsev Obelisk on Vasilievsky Island (1798–1801), and a galaxy of Derzhavin's odes.

Heavy infantry consisted of heavily armed and armoured infantrymen who were trained to mount frontal assaults and/or anchor the defensive center of a battle line. This differentiated them from light infantry who were relatively mobile and lightly armoured skirmisher troops intended for screening, scouting, and other tactical roles unsuited to soldiers carrying heavier loads. Heavy infantry typically made use of dense battlefield formations, such as shield wall or phalanx, multiplying their effective weight of arms with force concentration.

Heavy infantry were critical to many ancient armies, which first attested by the Sumerians in the Stele of the Vultures. It was also used by rival Assyrian and Persian Sparabara, then by Greek hoplites, Macedonian phalangites, and Roman legionaries. After the fall of Rome, heavy infantry declined in Europe but returned to dominance in the Late Middle Ages with Swiss pikemen and German Landsknechts. With the rise of firearms during early modern warfare, dense formations became increasingly infeasible, and heavy armours were either ineffective or too cumbersome to be tactically useful. By the early 18th century, heavy infantry were replaced by line infantry armed with muskets and bayonets and wearing little to no armour.

A peltast (Ancient Greek: πελταστής, peltastēs) was a type of light infantry originating in Thrace and Paeonia and named after the kind of shield they carried. Thucydides mentions the Thracian peltasts, while Xenophon in the Anabasis distinguishes the Thracian and Greek peltast troops.

The peltast often served as a skirmisher in Hellenistic armies. In the Middle Ages, the same term was used for a type of Byzantine infantryman.