This course was most natural for the Belgae, who were brought by neighbourhood and manifold intermixture into closer relation to the Germans who had crossed the Rhine, and moreover, with their less-developed culture, probably felt themselves at least as much akin to the Suebian of alien race as to their cultivated Allobrogian or Helvetic countryman.

But the southern Celts also, among whom now as already mentioned, the considerable canton of the Sequani (about Besangon) stood at the head of the party hostile to the Romans, had every reason at this very time to call in the Germans against the Romans who immediately threatened them; the remiss government of the senate and the signs of the revolution preparing in Rome, which had not remained unknown to the Celts, made this very moment seem suitable for ridding themselves of the Roman influence and primarily for humbling the Roman clients, the Haedui.

A rupture had taken place between the two cantons respecting the tolls on the Saone, which separated the territory of the Haedui from that of the Sequani, and about the year 683 the German prince Ariovistus with some 15,000 armed men had crossed the Rhine as condottiere of the Sequani.
Ariovistus on the Middle Rhine The war was prolonged for some years with varying success; on the whole the results were unfavourable to the Haedui.

Their leader Eporedorix at length called out their whole clients, and marched forth with an enormous superiority of force against the Germans.
These obstinately refused battle, and kept themselves under cover of morasses and forests.

It was not till the clans, weary of waiting, began to break up and disperse, that the Germans appeared in the open field, and then Ariovistus compelled a battle at Admagetobriga, in which the flower of the cavalry of the Haedui were left on the field.