Caesar broke off negotiations and instructed his men not to retaliate to prevent the Suebi from claiming that they were induced into a trap by their accepting an opportunity to talk.

[4] The following battle resulted in a Roman victory, which secured the eastern borderlands of Gaul, and allowed the temporary construction of Caesar's Rhine bridges for a tactical punitive assault staged in western Germania.

[10] Diviciacus, the head of the Aeduan government and spokesmen for the Gallic delegation, expressed concern over Ariovistus' conquests and for the hostages he had taken.

[11][12] Diviciacus demanded that Caesar defeat Ariovistus and remove the threat of a Germanic invasion otherwise they would have to seek refuge in a new land.

[14] Although Ariovistus assured Caesar that the Aedui hostages would be safe as long as they continued their yearly tribute, he took the position that he and the Romans were both conquerors and that Rome had no jurisdiction over his actions.

[15] With the attack of the Harudes on the Aedui and the report that a hundred clans of Suebi were trying to cross the Rhine into Gaul, Caesar had the justification he needed to wage war against Ariovistus in 58 BC.

[16][15] Caesar was not far away, probably at or near Bibracte, where he had just won a major victory over the Helvetii and other Celtic tribes, and had disposed of the remaining Boii, allowing them to settle in Aeduan land.

Ariovistus, being a skilled general in his own right, identified Vesontio as the key to the strategic Doubs valley and marched for it, but Caesar, probably relying on intelligence from the Gauls, arrived there first and established a main base.

The army was moving only 7 miles per day and was relying on Diviciacus to lead them through open country; thus, it is probably safe to assume there were no Roman roads between Besançon and Belfort at that time.

[17] The meeting of the two on a high mound between the camps with the bodyguards a few hundred yards away is surely a rare event in the history of parlays.

The classical civilizations throughout their long literary periods consistently characterized the peoples of the north and east as barbari, usually rendered in English as "barbarians".

Making a point to emphasize that he could not trust the Germans, Caesar sent two junior officers, Gaius Valerius Procillus and Marcus Mettius.

The Germanic tribes had developed a special force consisting of cavalry mixed with equal numbers of light infantry whose only function was to support cavalrymen, individually or in units, who had become enmeshed in combat.

Caesar claims the Germanic side did not attack in force because their wise women had pronounced from their divinations that they should not engage in battle before the new moon.

Dio Cassius notes the presence of Germans on the slope of the hill behind the camp, where the Porta Quaestoria, the gate where provisions were brought in, would have been.

The next day Caesar used the auxiliaries from the forward camp as cover while he brought all six rested and fed legions to a starting line before it in acies triplex formation.

The Germans formed by ethnic group before the Romans: Harudes, Marcomanni, Triboci, Vangiones, Nemetes, Sedusii and Suebi.

The Germanic forces responded by charging with such speed that the Romans were unable to cast pila and the fight entered the swordplay stage immediately.

The Germans crowded into a phalanx and began to push the Romans backward, even though the latter jumped up on the shields of the enemy to thrust them downward.

A cavalry officer, Publius Licinius Crassus, from his advantageous position on his horse, grasped what was happening and on his own initiative ordered the third line of battle (the infantry reserve) into action in support of the Roman left.

That decision was usually reserved to senior officers[citation needed] but Crassus won high praise for it after the battle and was probably slated for rapid advancement.

The enemy line broke and ran for the Rhine, which was 15 miles (24 km) away, women and all, with the Roman cavalry in hot pursuit.

In just a few days, the capability had been removed from the Suebi of mounting any offensive over or on the Rhine, which they assiduously avoided for some time to come, taking refuge in the Black Forest as the future Alamanni.