why did the romans use an eagle as a symbol
Aquila (Roman) The eagle was extremely important to the Roman military, beyond merely being a symbol of a legion. A lost standard was considered an extremely grave occurrence, and the Roman military often went to great lengths to both protect a standard and to recover it if lost; for example, see the aftermath of the Battle of the Teutoburg Forest, where the Romans spent decades attempting to recover the lost standards of three legions.
Flag of Mexico Red, white, and green are the colors of the national liberation army in Mexico. The central emblem is the Mexican coat of arms, based on the Aztec symbol for Tenochtitlan (now Mexico City), the center of the Aztec empire. It recalls the legend of an eagle sitting on a cactus while devouring a serpent that signaled to the Aztecs where to found their city, Tenochtitlan.[1] A ribbon in the national colors is at the bottom of the coat of arms. Throughout history, the flag has changed several times, as the design of the coat of arms and the length-width ratios of the flag have been modified. However, the coat of arms has had the same features throughout: an eagle, holding a serpent in its talon, is perched on top of a prickly pear cactus; the cactus is situated on a rock that rises above a lake. The coat of arms is derived from an Aztec legend that their gods told them to build a city where they spot an eagle on a nopal eating a serpent, which is now Mexico City.