Vangiones

thumb|right|The eleven prefectures of the Duke of Mainz in [[Notitia Dignitatum. Castle Vangionis is the 2nd up from the bottom in the left column.]] The Vangiones appear first in history as an ancient Germanic tribe of unknown provenance. They threw in their lot with Ariovistus in his bid of 58 BC to invade Gaul through the Doubs river valley and lost to Julius Caesar in a battle probably near Belfort. After some Celts evacuated the region in fear of the Suebi, the Vangiones, who had made a Roman peace, were allowed to settle among the Mediomatrici in northern Alsace. (Metz however is now in Lorraine). They gradually assumed control of the Celtic city of Burbetomagus, later Worms.

The emperor Augustus cultivated them as allies, intending to invade Germany through the region between the Rhine and the Danube. He had Drusus place two forts among the Vangiones, castrum Moguntiacum (13 BC, later Mainz) and one of unknown name (14 BC) at Worms. From there troops of the Vangiones were inducted into the Roman army. When he changed his mind after the Battle of Teutoburg Forest, the Vangiones were used for garrison duty on the far-flung northern frontier of the province of Britannia, Hadrian's Wall.