The term "battalion" was first used in Italian as battaglione no later than the 16th century. It derived from the Italian word for battle, battaglia. The first use of battalion in English was in the 1580s, and the first use to mean "part of a regiment" is from 1708.

What is the oldest unit in the army?

The 3d U.S. Infantry, traditionally known as "The Old Guard," is the oldest active-duty infantry unit in the Army, serving our nation since 1784.

How many soldiers are in a battalion?

Battalions consist of four to six companies and can include up to about 1,000 soldiers. They can conduct independent operations of limited scope and duration and are usually commanded by a lieutenant colonel. There are combat arms battalions, as well as combat support and combat service support battalions.