The UNSC Army can trace its history back to 2162, where the newly formed UN Army defeated Frieden and Koslovic forces in South America, although its official formation came with the establishment of the UNSC in 2163. The Army went through several roles and functions throughout its long history, initially serving, under the guise of the UN Army, as the UN's premier fighting force during the Rainforest Wars. As the war spread through the solar system and the UNSC Navy and Marine Corps established themselves in the niche of expeditionary warfare, the Army re-roled as a garrison force able to keep the peace on restless colonies and fend off concentrated attacks from irregular forces. This was a role it continued in throughout the Insurrection, where it faced persistent low-level insurgency on