Furor Teutonicus
Furor Teutonicus "Teutonic Fury" is a Latin phrase referring to the proverbial fierceness of the Teutones, or more generally the Germanic tribes of the Roman Empire period.
The original expression is generally attributed to the Roman poet Marcus Annaeus Lucanus, also know as Lucan. It occurs for the first time in his work bellum civile/Pharsalia. Lucan used the term to describe what he believed to be the outstanding characteristic of the Germanic tribe called the Teutones: a mad, merciless (also to themselves) rage in battle.
The Teutons met with the armies of the Roman Empire in the eastern Alps around 113 BC. The Romans, under the command of the Consul Papirius Carbo, tried to lure the tribe into a trap, but they underestimated their military potential and lost the Battle of Noreia. Several other encounters, for example the Battle of Arausio (105 BC) also lead to defeat of the Romans. This led to fear of invasion by the Teutons, even though in hindsight it turned out to be an unwarranted fear, as there was no motivation for the Teutons to occupy Rome.
The Teutons were defeated by Gaius Marius in 102 BC, but other Germanic tribes remained a worry for the Roman Empire until its conquest and destruction by Germanic mercenaries under the Germanic chieftain Odoacer.