According to a legend recounted by Livy, the king Ambigatus sent his sister's sons Bellovesus and Segovesus in search of new lands to settle because of overpopulation in their homeland.
While Bellovesus is said to have led the Gallic invasion of northern Italy, Segovesus reportedly headed towards the Hercynian Forest, in Western Central Europe.
It is made up of the prefix sego- ('strength, victory') attached to uesus, meaning 'worthy, good, deserving', itself from Proto-Celtic *wesus ('excellent, noble'; cf.
The legend is recounted by the Roman historian Livy in his Ab Urbe Condita Libri, written in the late 1st century BC:... Gaul under [Ambigatus'] sway grew so rich in corn and so populous, that it seemed hardly possible to govern so great a multitude.
The king, who was now an old man and wished to relieve his kingdom of a burdensome throng, announced that he meant to send Bellovesus and Segovesus, his sister's sons, two enterprising young men, to find such homes as the gods might assign to them by augury; and promised them that they should head as large a number of emigrants as they themselves desired, so that no tribe might be able to prevent their settlement.