Roman Legionary Eagle (Aquila) 

An Aquila is an eagle used as a symbolic symbol in Ancient Rome as a of standard legion.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.