The History of the Army

An army is an organized, land-based military fighting unit. From the ancient world to modern times, the organization and composition of armies has varied considerably.

The earliest armies consisted of warriors in horse-drawn chariots; of infantry--armed foot soldiers; and of cavalry--armed soldiers on horseback. These units were sometimes accompanied by engineers who operated siege weapons and by supply trains to feed and outfit the fighters.

With the introduction of cannon in the 15th century, artillery units were added to the combat sections of armies. In the 19th and 20th centuries, as a result of great advances in technology, other units were added: signal troops, engineer corps for building bridges and entrenchments, medical units, administrative troops, mechanized units to replace cavalry, transportation and communication units, and explosives and munitions experts. The number of such backup or support units has tended to increase as warfare has become more sophisticated.

Recruitment for armies takes different forms. Soldiers may be volunteers, conscripts, or mercenaries. Volunteers fight willingly, usually for a cause or a country. Conscripts are drafted by their country to serve in its armed forces (see Conscription). Mercenaries serve for pay. They are not necessarily citizens of the country they fight for.

The command structure of armies has undergone considerable change in the course of centuries. The earliest armies followed a single leader, either a tribal chief or a king. As nations grew in size and armies became larger, it was necessary to divide command among officers, of whom generals were the highest rank. Officers, some of whom were professional soldiers, normally came from the wealthiest class in a society. They alone had the money to pay soldiers, buy weapons, and supply horses for war.

In the 20th century, with the spread of both democratic and socialist types of government, permanent officer classes based on wealth or heredity have tended to disappear. Except in states that have military dictatorships, the army is kept under the control of elected civilian officials. Officers are promoted from within the ranks or are trained at military schools (see Military Education).

Command structures of modern armies vary somewhat. The officer ranking system discussed here is based on that of the United States Army as it has developed since World War II.

All army personnel are ranked according to level, from the lowest level--privates--to the highest level--generals. Above privates there are three levels of officers: noncommissioned officers, warrant officers, and commissioned officers. The difference between noncommissioned officers and commissioned officers is one of training and also of authority. Commissioned officers are graduates of military academies or of officer training schools.

Noncommissioned officers include corporals and sergeants. There are several ranks of sergeants including staff sergeant, master sergeant, and command sergeant major. The duties of these officers vary considerably, depending on the complexity of the makeup of an army. Some are in combat command positions, others in backup units such as maintenance, transportation, or communications. Noncommissioned officers are promoted from within the body of enlisted personnel.

Warrant officers are neither commissioned nor noncommissioned officers, but in rank they are between the two. In the modern army warrant officers are highly trained technical experts who usually operate in one area of specialization throughout their whole military career. Most helicopter pilots, for instance, are warrant officers. They may also operate in an advisory or administrative position, but they do not command troops. Although they remain warrant officers, their pay schedules may rise to that of some commissioned officers.

The levels of commissioned officers are as follows:

1. Line officers, also called company grade officers or junior officers, include second lieutenants, lieutenants, and captains. The highest rank, the captain, is usually in command of a company, a unit of 160 soldiers in the United States Army. A lieutenant commands a platoon, a unit of 38 soldiers. He is assisted by a second lieutenant.

2. Field grade officers, also called senior officers, are majors, lieutenant colonels, and colonels. Colonels command brigades, units of 3,800 soldiers. Lieutenant colonels command battalions, units of 817 soldiers. They are assisted by majors.

3. General officers are the highest ranking officers in an army. They are brigadier general, major general, lieutenant general, and general. Some European armies have as the highest rank the field marshal. The United States has conferred the unique title of general of the armies on a few generals