In the reign of Tarquinius Priscus at Rome, the supreme government of the Celts, who compose the third part of Gaul, was in the hands of the Biturigians: they gave a king to the Celtic nation.

This was Ambigatus, one very much distinguished by his merit, and both his great prosperity in his own concerns and in those of the public; for under his administration Gaul was so fruitful and so well peopled, that so very great a population appeared scarcely capable of being restrained by any government.

He being now advanced in years, and anxious to relieve his kingdom of so oppressive a crowd, declares his intention to send his sister's sons, Bellovesus and Sigovesus, two enterprising youths, into whatever settlements the gods should grant them by augury: that they should take out with them as great a number of men as they pleased, so that no nation might be able to obstruct them in their progress.

Then to Sigovesus the Hercynian forest was assigned by the oracle: to Bellovesus the gods marked out a much more cheering route into Italy.

He carried out with him from the Biturigians, the Arvernians, the Senonians, the AEduans, the Ambarrians, the Carnutians, and the Aulercians, all that was superfluous in their population.