It is quite ironic that the greatest and most efficient empire in history was probably that of Rome, yet three of the most smashing defeats of an army in military history came at her expense. One was during her rise just before she was an international power, the 2nd occurred during her zenith, and the third was when she was decadent and near collapse. 1. In 216 B.C., Hannibal inflicted perhaps the most devastating defeat ever on an army in military history, annhilating 8 legions, the largest Rome ever pitted on the field, within few hours. His classic double-envelopment resulted in the destruction of 80% of a total Roman force of over 90,000 foot and horse. Cannae would enter military textbooks as the model of a perfect battle of annihilation, and never again would an army rely solely on superior numbers of infantry. Cannae was not only one of the bloodiest battles of ancient times, it was one of the bloodiests battles of all time. Around 70,000 Romans and a few thousand Carthaginians were killed in a few hours of fighting. There are few instances in history were such a one-sided battle has so many men been killed. And it was all thanks to Hannibal's genius. 2. In A.D. 9, three legions led by Q. Varus, numbering some 15,000 soldiers and auxiliary cavalry, practically all perished at the Teutoburger Wald (the Rhineland) at the hands of Arminius I, known in Germany as Hermann. Germany would prove unqonquerable to Rome. 3. In A.D. 378, the Goths led by Fritigern, destroyed the 60,000 force of foot and horse under Valens, the Byzantine emperor. 50,000 or so swift Gothic horsemen joined the same number of infantry and descended upon and surrounded Valens' force near Adrianople, a town in modern Bulgaria. The result was comparable to Cannae, with 3/4 of Valens', including himself, wiped out. This smashing win marked the arrival of the Goths in western Europe and altered warfare from infantry to cavalry dominance for the next millenia or so.