Latinized variant of the Proto-Germanic name Irmin - "great" or of Herman - "warrior".
Arminius, also known as Armin or Herman was a chieftain of the Proto-Germanic Cherusci who defeated a Roman army in the Battle of the Teutoburg Forest. His influence held an allied coalition of Germanic tribes together in opposition to the Romans but after decisive defeats by the Roman general Germanicus, nephew of the Emperor Tiberius, his influence waned and he was assassinated on the orders of rival Germanic chiefs. Although Arminius was ultimately unsuccessful in forging unity among the Proto-Germanic tribes, the loss of the Roman legions in the Teutoburg forest had a far-reaching effect on the subsequent history of both the ancient Germanic tribes and on the Roman Empire. The Romans were to make no more concerted attempts to conquer and permanently hold Germania beyond the river Rhine.
Born in 18 or 17 BC as son of the Cheruscan war chief Segimerus, Arminius was trained as a Roman military commander and attained Roman citizenship and the status of equestrian (petty noble) before returning to Germania and driving the Romans out.