The 5th Infantry Regiment, formed by an act of Congress on March 3, 1815, was part of the reorganization that reduced the number of infantry and rifle regiments following the War of 1812. Initially, the regiment was one of the eight infantry regiments established for peacetime. Over time, it has participated in major American conflicts since 1808 and has been known for its historical contributions.
For more detailed history, you can refer to the Wikipedia page: 5th Infantry Regiment (United States)