The 5th Infantry Regiment (nicknamed the "Bobcats") is an infantry regiment of the United States Army that traces its origins to 1808. Origins: War of 1812. The 5th Infantry Regiment was created by an Act of Congress of 3 March 1815, which reduced the Regular Army from the 46 infantry and 4 rifle regiments it fielded in the War of 1812 to a peacetime establishment of 8 infantry regiments (reduced to 7 in 1821). The Army's current regimental numbering system dates from this act.
https://en.wikipedia.org/wiki/5th_Infantry_Regiment_(United_States)