Infantry in the context of Designated marksman rifle

The Macedonian phalanx (Greek: Μακεδονική φάλαγξ) was an infantry formation developed by Philip II from the classical Greek phalanx, of which the main innovation was the use of the sarissa, a 6-metre pike. It was famously commanded by him during the rise of Macedon and by his son Alexander the Great during his conquest of the Achaemenid Empire and his other campaigns between 336 and 325 BC.

The Macedonian phalanx model then spread throughout the Hellenistic world, where it became the standard battle formation for pitched battles. During the Second Macedonian War (200–197 BC), Roman-Seleucid War (191–188 BC) and Third Macedonian War (171–168 BC) against the Roman Republic, the Hellenistic phalanx, both the Antigonid phalanx and the Seleucid phalanx, appeared less adaptable to changing conditions on the battlefield against the more flexible Roman legions.

Combined arms is an approach to warfare that seeks to integrate different combat arms of a military to achieve mutually complementary effects—for example, using infantry and armour in an urban environment in which each supports the other.

According to the strategist William S. Lind, combined arms can be distinguished from the concept of "supporting arms" as follows:

The military nature of Mycenaean Greece (c. 1800–1050 BC) in the Late Bronze Age is evident by the numerous weapons unearthed, warrior and combat representations in contemporary art, as well as by the preserved Greek Linear B records. The Mycenaeans invested in the development of military infrastructure with military production and logistics being supervised directly from the palatial centres.

Late Bronze Age Greece was divided into a series of warrior kingdoms, the most important being centered in Mycenae, to which the culture of this era owes its name, Tiryns, Pylos and Thebes. From the 15th century BC, Mycenaean power started expanding towards the Aegean, the Anatolian coast and Cyprus. Mycenaean armies shared several common features with other contemporary Late Bronze Age powers: they were initially based on heavy infantry, with spears, large shields and in some occasions armor. In the 13th century BC, Mycenaean units underwent a transformation in tactics and weaponry and became more uniform and flexible and their weapons became smaller and lighter. Some representative types of Mycenaean armor/weapons were the boar's tusk helmet and the "Figure-of-eight" shield. Moreover, most features of the later hoplite panoply of Classical Greece were already known at this time.

The United States Marine Corps (USMC), also referred to as the United States Marines or simply the Marines, is the maritime land force service branch of the United States Armed Forces. It is responsible for conducting expeditionary and amphibious operations through combined arms, implementing its own infantry, artillery, aerial, and special operations forces. The U.S. Marine Corps is a part of the United States Department of Defense and is one of the six armed forces of the United States and one of the eight uniformed services of the United States.

The Marine Corps has been part of the United States Department of the Navy since 30 June 1834 with its sister service, the United States Navy. The USMC operates installations on land and aboard sea-going amphibious warfare ships around the world. Additionally, several of the Marines' tactical aviation squadrons, primarily Marine Fighter Attack squadrons, are also embedded in Navy carrier air wings and operate from the aircraft carriers.

The Battle of the Kerch Peninsula, which commenced with the Soviet Kerch-Feodosia Landing Operation (Russian: Керченско-Феодосийская десантная операция, romanized: Kerchensko-Feodosiyskaya desantnaya operatsiya) and ended with the German Operation Bustard Hunt (German: Unternehmen Trappenjagd), was a World War II battle between Erich von Manstein's German and Romanian 11th Army and the Soviet Crimean Front forces in the Kerch Peninsula, in the eastern part of the Crimean Peninsula. It began on 26 December 1941, with an amphibious landing operation by two Soviet armies intended to break the Siege of Sevastopol. Axis forces first contained the Soviet beachhead throughout the winter and interdicted its naval supply lines through aerial bombing. From January through April, the Crimean Front launched repeated offensives against the 11th Army, all of which failed with heavy losses. The Red Army lost 352,000 men in the attacks, while the Axis suffered 24,120 casualties. Superior German artillery firepower was largely responsible for the Soviet debacle.

On 8 May 1942, the Axis attacked in a major counteroffensive codenamed Trappenjagd which concluded by around 19 May 1942 with the defeat of the Soviet defending forces. Manstein used a large concentration of airpower, heavily armed infantry divisions, concentrated artillery bombardments and amphibious assaults to break through the Soviet front in its southern portion in 210 minutes, swing north with the 22nd Panzer Division to encircle the Soviet 51st Army on 10 May and annihilate it on 11 May. The remnants of the 44th and 47th armies were pursued to Kerch, where the last pockets of organized Soviet resistance were defeated by 19 May. The decisive element in the German victory was the campaign of airstrikes against the Crimean Front by Wolfram von Richthofen's 800 aircraft VIII. Fliegerkorps, which flew an average of 1,500 sorties per day in support of Trappenjagd and constantly attacked Soviet field positions, armored units, troop columns, medical evacuation ships, airfields, and supply lines. German bombers used up to 6,000 canisters of SD-2 anti-personnel cluster munitions to kill masses of fleeing Soviet infantrymen.

A pike is a long thrusting spear formerly used in European warfare from the Late Middle Ages and most of the early modern period, and wielded by foot soldiers deployed in pike square formation, until it was largely replaced by bayonet-equipped muskets. The pike was particularly well known as the primary weapon of Spanish tercios, Swiss mercenaries, German Landsknecht units and French sans-culottes. A similar weapon, the sarissa, had been used in antiquity by Alexander the Great's Macedonian phalanx infantry.

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.

Artillery consists of ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and led to heavy, fairly immobile siege engines. As technology improved, lighter, more mobile field artillery cannons were developed for battlefield use. This development continues today; modern self-propelled artillery vehicles are highly mobile weapons of great versatility generally providing the largest share of an army's total firepower.

Originally, the word "artillery" referred to any group of soldiers primarily armed with some form of manufactured weapon or armour. Since the introduction of gunpowder and cannon, "artillery" has largely meant cannon, and in contemporary usage, usually refers to shell-firing guns, howitzers, and mortars (collectively called barrel artillery, cannon artillery or gun artillery) and rocket artillery. In common speech, the word "artillery" is often used to refer to individual devices, along with their accessories and fittings, although these assemblages are more properly called "equipment". However, there is no generally recognized generic term for a gun, howitzer, mortar, and so forth: the United States uses "artillery piece", but most English-speaking armies use "gun" and "mortar". The projectiles fired are typically either "shot" (if solid) or "shell" (if not solid). Historically, variants of solid shot including canister, chain shot and grapeshot were also used. "Shell" is a widely used generic term for a projectile, which is a component of munitions.

Historically, cavalry (from the French word cavalerie, itself derived from cheval meaning "horse") are groups of soldiers or warriors who fight mounted on horseback. Until the 20th century, cavalry were the most mobile of the combat arms, operating as light cavalry in the roles of reconnaissance, screening, and skirmishing, or as heavy cavalry for decisive economy of force and shock attacks. An individual soldier in the cavalry is known by a number of designations depending on era and tactics, such as a cavalryman, horseman, trooper, cataphract, knight, drabant, hussar, uhlan, mamluk, cuirassier, lancer, dragoon, samurai or horse archer. The designation of cavalry was not usually given to any military forces that used other animals or platforms for mounts, such as chariots, camels or elephants. Infantry who moved on horseback, but dismounted to fight on foot, were known in the early 17th to the early 18th century as dragoons, a class of mounted infantry which in most armies later evolved into standard cavalry while retaining their historic designation.

Cavalry had the advantage of improved mobility, and a soldier fighting from horseback also had the advantages of greater height, speed, and inertial mass over an opponent on foot. Another element of horse mounted warfare is the psychological impact a mounted soldier can inflict on an opponent.

Military tactics encompasses the art of organizing and employing fighting forces on or near the battlefield. They involve the application of four battlefield functions which are closely related – kinetic or firepower, mobility, protection or security, and shock action. Tactics are a separate function from command and control and logistics. In contemporary military science, tactics are the lowest of three levels of warfighting, the higher levels being the strategic and operational levels. Throughout history, there has been a shifting balance between the four tactical functions, generally based on the application of military technology, which has led to one or more of the tactical functions being dominant for a period of time, usually accompanied by the dominance of an associated fighting arm deployed on the battlefield, such as infantry, artillery, cavalry or tanks.

Light infantry refers to certain types of lightly equipped infantry throughout history. They have a more mobile or fluid function than other types of infantry, such as heavy infantry or line infantry. Historically, light infantry often fought as scouts, raiders, and skirmishers. These are loose formations that fight ahead of the main army to harass, delay, disrupt supply lines, engage the enemy's own skirmishing forces, and generally "soften up" an enemy before the main battle. Light infantrymen were also often responsible for screening the main body of a military formation.

Following World War II, the term "light infantry" has evolved to include rapid-deployment units (including commando and airborne units) that emphasize speed and mobility over armor and firepower. Some units or battalions that historically held a skirmishing role retain their designation "light infantry" for the sake of tradition.

Irregular military is any military component distinct from a country's regular armed forces, representing non-standard militant elements outside of conventional governmental backing. Irregular elements can consist of militias, private armies, mercenaries, or other non-state actors, though no single definition exists beyond exclusion from national service. Without standard military unit organization, various more general names are often used; such organizations may be called a troop, group, unit, column, band, or force. Irregulars are soldiers or warriors that are members of these organizations, or are members of special military units that employ irregular military tactics. This also applies to irregular infantry and irregular cavalry units.

Irregular warfare is warfare employing the tactics commonly used by irregular military organizations. This often overlaps with asymmetrical warfare, avoiding large-scale combat and focusing on small, stealthy, hit-and-run engagements.

The Battle of Lechfeld, also known as the Second Battle of Lechfeld, was a series of military engagements over the course of three days from 10–12 August 955 in which the Kingdom of Germany, led by King Otto I the Great, fought the Hungarian army led by Harka Bulcsú and the chieftains Lél and Súr. The traditional view is that with the German victory, further invasions by the Magyars into Latin Europe ended, although it is more accurate to say that the battle resulted in a stalemate between the Hungarians and Germans over the next several decades.

The Hungarians invaded the Duchy of Bavaria in late June or early July 955 with 8,000–10,000 horse archers, infantry, and siege engines, intending to draw the main German army, under Otto I, into battle in the open field and destroy it. The Hungarians laid siege to Augsburg on the river Lech. Otto I advanced to relieve the city with an army of 8,000 heavy cavalry and infantry, divided into eight legions.

The Beiyang Army (Chinese: 北洋軍; pinyin: Běi Yáng Jūn; lit. 'Northern Ocean Army'), named after the Beiyang region, was an army established by Yuan Shikai in 1895. It was the centerpiece of a general overhaul of the Qing military system in the wake of the Boxer Rebellion and the First Sino-Japanese War, becoming the dynasty's first regular army in terms of its training, equipment, and structure. The Beiyang Army played a major role in Chinese politics for at least three decades and arguably right up to 1949. It played an instrumental role in the 1911 Revolution against the Qing dynasty, and, by dividing into warlord factions known as the Beiyang clique (Chinese: 北洋軍閥; pinyin: Běiyáng Jūnfá), ushered in a period of regional division.

The Beiyang Army had its origins in the Newly Created Army established in late 1895 under Yuan Shikai's command, after China was defeated in the First Sino-Japanese War. Unlike its predecessors, it had a formal structure with infantry, cavalry, artillery, and logistical branches, and maintained strict training and discipline. The brigade-sized force was expanded over the years with new recruits and by incorporating other units, before serving as the core of a larger army after Yuan was appointed the Viceroy of Zhili and Minister of Beiyang in 1901. The tensions in Manchuria leading up to the Russo-Japanese War caused Empress Dowager Cixi to accept Yuan's request to raise more divisions, and he also used his influential position in the Army Reorganization Bureau to prioritize its funding. By 1907 the Beiyang Army had 60,000 men organized in six divisions, some of whom served in the Inner City of Beijing as the emperor's palace guard, and on the eve of the 1911 Revolution it was the strongest military force of the Qing dynasty.

The United States Army Command and General Staff College (CGSC or USACGSC) is a staff college for United States Army located at Fort Leavenworth, Kansas. The college was established in 1881 by William Tecumseh Sherman as the School of Application for Infantry and Cavalry (later simply the Infantry and Cavalry School), a training school for infantry and cavalry officers.

In 1907 it changed its title to the School of the Line. The curriculum expanded throughout World War I, World War II, the Korean War, and the Vietnam War and continues to adapt to include lessons learned from current conflicts. It provides Professional Military Education to officers of the United States Army, as well as foreign military officers.

Land warfare or ground warfare is the process of military operations eventuating in combat that takes place predominantly on the battlespace land surface of the planet.

Land warfare is categorized by the use of large numbers of combat personnel employing a diverse set of combat skills, methods and a wide variety of weapon systems and equipment, conducted in diverse terrains and weather environments. Land warfare, by virtue of being conducted in defence of urban and rural population areas, dominates the study of war, and is a focus for most national defence policy planning and financial considerations.

The Western Front was one of the main theatres of war during World War I. Following the outbreak of war in August 1914, the German Army opened the Western Front by invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The German advance was halted with the Battle of the Marne. Following the Race to the Sea, both sides dug in along a meandering line of fortified trenches, stretching from the North Sea to the Swiss frontier with France, the position of which changed little except during early 1917 and again in 1918.

Between 1915 and 1917 there were several offensives along this front. The attacks employed massive artillery bombardments and massed infantry advances. Entrenchments, machine gun emplacements, barbed wire, and artillery repeatedly inflicted severe casualties during attacks and counter-attacks and no significant advances were made. Among the most costly of these offensives were the Battle of Verdun, in 1916, with a combined 700,000 casualties, the Battle of the Somme, also in 1916, with over a million casualties, and the Battle of Passchendaele, in 1917, with 487,000 casualties.

A janissary (UK: /ˈdʒænɪsəri/ JAN-iss-ər-ee, US: /-sɛri/ -⁠err-ee; Ottoman Turkish: یڭیچری, romanized: yeñiçeri, IPA: [jeˈŋit͡ʃeɾ̞i], lit. 'new soldier') was a member of the elite infantry units that formed the Ottoman sultan's household troops. They were the first modern standing army, and perhaps the first infantry force in the world to be equipped with firearms, adopted during the reign of Murad II (r. 1421–1444, 1446–1451). The corps was established under either Orhan or Murad I, and dismantled by Mahmud II in 1826.

Janissaries began as an elite corps made up through the devşirme system of child levy enslavement, by which Christian boys, chiefly from the Balkans, were taken, levied, subjected to forced circumcision and forced conversion to Islam, and incorporated into the Ottoman army. They became famed for internal cohesion cemented by strict discipline and order. Unlike typical slaves, they were paid regular salaries. Forbidden to marry before the age of 40 or engage in trade, their complete loyalty to the Ottoman sultan was expected. By the 17th century, due to a dramatic increase in the size of the Ottoman standing army, the corps' initially strict recruitment policy was relaxed. Civilians bought their way into it in order to benefit from the improved socio-economic status it conferred upon them. Consequently, the corps gradually lost its military character, undergoing a process that has been described as "civilianization".