While Segovesus headed towards the Hercynian Forest, Bellovesus is said to have led the Gallic invasion of the Po Valley during the legendary reign of the fifth king of Rome, Tarquinius Priscus (616–579 BC), where he allegedly conquered the Etruscans and founded the city of Mediolanum (Milan).
[5][6] According to historian Venceslas Kruta, the story of Bellovesus "is probably the legendary construction of a 'myth of origins', likely Insubrian, which integrates various elements borrowed from Celtic, Cisalpine and Transalpine traditions, as well as Massaliote and Etrusco-Italian.
Taking out with him the surplus population of his tribes, the Bituriges, Arverni, Senones, Haedui, Ambarri, Carnutes, and Aulerci, he marched with vast numbers of infantry and cavalry into the country of the Tricastini.The Alps represented an insurmountable hurdle since no road had been built across them yet.
Having arrived in Italy, the Gauls defeated the Etruscans near the Ticino River, then settled in an area later called Insubria and, according to Livy, "bore the same name as an Haeduan canton".
Another group made up of Cenomani and led by Etitovius followed their track and, with the approval of Bellovesus, crossed the Alps by the same pass before settling around the present-day cities of Brescia and Verona.