[16] Before the arrival of Julius Caesar in Gaul, the Sequani had taken the side of the Arverni against their rivals the Aedui and hired the Suebi under Ariovistus to cross the Rhine and help them (71 BC).
Although his assistance enabled them to defeat the Aedui, the Sequani were worse off than before, for Ariovistus deprived them of a third of their territory and threatened to take another third,[11] while subjugating them into semi-slavery.
A triumphal arch at Vesontio (Besançon), which in return for this service was made a colony, possibly commemorates this victory.
[11] Diocletian added Helvetia, and part of Germania Superior to Sequania, which was now called Provincia Maxima Sequanorum, Vesontio receiving the title of Metropolis civitas Vesontiensium.
Later, when Rome was no longer able to afford protection to the inhabitants of Gaul, the Sequani became merged in the newly formed Kingdom of Burgundy.