Ariovistus (ârˌēōvĭsˈtəs) [key], fl. 58 B.C., Germanic chieftain, leader of the Suebi. He crossed the Rhine c.71 B.C., defeated the Aedui, and came to dominate much of Gaul (see Gallic Wars). In 60 B.C. he was made a friend and ally of Rome, but his power threatened the Romans in Gaul, and Julius Caesar, soon after winning the great victory of Bibracte over the Helvetii, undertook a campaign against him. Caesar defeated Ariovistus somewhere in Upper Alsace in 58 B.C.