Infantry (or Infantrymen) are soldiers who fight primarily on foot, using personal weapons. They may arrive on scene in various ways, and are deployed either in formations or as skirmishers and guerillas. In the modern period, the term "infantryman" is reserved for the most basic of infantry troops, the rifleman.
Infantry have been the core of most armies throughout history. In ancient times the most prominent formations were the phalanx and later the more sophisticated legion, which could reach several thousand men in size. During the end of Antiquity and some parts of the Middle Ages, cavalry (mounted units) were often considered superior to infantry. The arrogance of many mounted knights, charging disorganized into schiltrons of infantry formations often resulted in disaster for cavalry, however. Organized infantry formations tended to dominate the battlefield, in combined use with cavalry, projectile weapons, and terrain tactics until firearms and explosives revolutionized warfare.
Although the longbow would remain significantly more powerful than the newly invented musket for some hundreds of years - longbows had greater range, accuracy, penetrating power and rate of fire than early firearms - it required great skill to use effectively. It took a lifetime of training to become an effective archer, where to raise an army of musketeers simply needed ample numbers of men who could be trained in weeks or months, enough money, and access to manufacturing facilities for guns and powder. From the late Middle Ages on, industrialisation saw rural aristocracies weaken, cities became richer, and large, easily raised forces of relatively untrained infantry ruled the battlefield. With cavalry now lighter and unarmoured, the pike became an important close-range defence for bodies of well-drilled infantry.
Before the development of railroads in the 19th century, infantry armies got to the battlefield by walking, or sometimes by ship. In the 1890s and later, some countries used bicycle infantry, but the real revolution in mobility started in the 1920s with the use of motor vehicles, resulting in motorised infantry. Action in World War II demonstrated the importance of protecting the soldiers while they are moving around, resulting in the development of mechanized infantry that uses armoured vehicles for transport. World War II also saw the first widespread use of airborne or parachute infantry, which played key roles in several campaigns in the European theater. During the Vietnam conflict, the US Army pioneered the use of helicopters to deliver large numbers of infantry quickly to and from key locations on the battlefield.
Modern-day infantry is supported by armoured fighting vehicles, artillery, and aircraft, but are still the only kind of military force that can take and hold ground, and thus remain essential to fighting wars.
- "I love the infantry because they are the underdogs. They are the mud-rain-frost-and-wind boys. They have no comforts, and they even learn to live without the necessities. And in the end they are the guys that wars can't be won without." Ernie Pyle
- "I'm convinced that the infantry is the group in the army which gives more and gets less than anybody else." Bill Mauldin, Up Front (1945)