Captain Ephraim Kirby Smith (1807–1847) of the Fifth Infantry wrote letters home from April 9, 1846, to January 27, 1847, about his experience in what became known as the Mexican–American War (1846–48). His nine letters were written near Matamoras, just outside of Mexico City. Smith includes descriptions of high-level decisions to remain in Mexican territory and documents the fate of several U.S. officers.