The Mexican Republican Army had been defeated during the First Mexican War, losing control of New Mexico, Utah, California, and part of Colorado. This defeat left many Mexicans with little love of the United States. During the French intervention, and the installation of the Emperor Maximilian, the army was renamed the Mexican Imperial Army. Although never threatened again, they spent most of their time fighting Apache Indians along the US frontier, until that region was transferred over to the CSA. Ironically, the army of Mexico played almost no role in the so-called Second Mexican War.