Some time before Caesar's governorship of Gaul (which began in 58 BC), the Gaulish Arverni and Sequani enlisted Ariovistus's aid in their war against the Aedui.

Their territory lay between their neighbors to the northeast, the Sequani, who occupied the Doubs river valley, and the Arverni in the Massif Central.

To avoid infringing on his allies for the moment, Ariovistus must have passed over the low divide between the Rhine and the Doubs in the vicinity of Belfort and then have approached the Aedui along the Ognon river valley.

[12] The sequence of events given by Caesar also seems to indicate that, when his governorship began in 58 BC, the Germans had been settled in Gaul for longer than one year.

Caesar, therefore, sent his ambassadors back to Ariovistus with his demands: that he bring no more of his people across the Rhine, and that he and his allies restore the hostages they had taken from the Aedui and undertake not to make war against them.

Ridiculing Rome's ability to protect its friends and boasting of Germanic invincibility, Ariovistus invited Caesar to attack him if he wished.

Cassius Dio, writing more than two centuries later, agrees, characterising Caesar as attempting to provoke a war to win glory and power while he took pains not to look like the aggressor.

At the same time that Caesar received Ariovistus's message, he heard from his Celtic allies that the Harudes were devastating the country of the Aedui and that 100 units of Suebi under the brothers Nasua and Cimberius were about to cross the Rhine.

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.

In one of his noted speeches he recalled them to duty and ended by threatening to march the next morning early with only the 10th legion, about whose valour he said he had no doubts at all.

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.

[14] 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.

Both Caesar's emissaries were rescued unharmed, to relate their harrowing adventures as the Germans debated (in their presence) whether they should be burned then or later.

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.

Most scholars consider Ariovistus to be derived from the Gaulish ario ("noble, free, advanced") and uid-, uidi-, uissu- ("perception, knowledge").

William Smith's Dictionary of Greek and Roman Biography and, under Ariovistus, suggests another derivation of the first element that seems to fit runic inscriptions known today.

The Indo-European linguist, Julius Pokorny, in Indogermanisches Etymologisches Woerterbuch (which is available on the Internet) simply states on Page 67 under ario-?