In the 2nd century AD, they entered into a confederation with other peoples which included the Quadi, Vandals, and Sarmatians against Rome. This was driven probably by greater tribal movements like the Goths to their north and east. According to the historian Eutropius, the forces of the Emperor Marcus Aurelius battled against the Marcomannic confederation for three years at the fortress of Carnuntum in Pannonia. He compared the war and Marcus Aurelius' success against the Marcomanni and their allies to the Punic Wars. The comparison was fair in that this war marked a turning point and had significant Roman defeats. It began in 166 and lasted to the end of Marcus Aurelius's death, involving the unheard-of defeats and the death of two Praetorian Guard commanders. It was in fact only a limited success since from the next century onwards the Danube was the main Roman battlefront until the collapse of the Roman Empire in the 5th Century.
See Also: Irminones