Celts who migrated from southern Germany to south and west of the Rhine in the 2nd century bc. In 102 bc they joined the Cimbri and Teutones in invading Italy and were defeated by Emperor Marius. Under pressure of Germanic migrations they attempted a mass migration into Roman Gaul in 58 bc. Julius Caesar drove them back. Augustus incorporated their territory into Belgic Gaul. Overrun in the 5th century by a succession of Alemanni, Franks, Swabians, and Burgundians their name is preserved in the formal name for Switzerland—the Helvetic Confederacy (or Helvetia).