The Insubres were a Gaulish^{[citation needed]} population settled in Insubria, in what is now Lombardy [1]. They were the founders of Milan (Mediolanum). Though ethnically Celtic at the time of Roman conquest (at the beginning of the 2nd century BC), they were most likely the result of the fusion of pre-existing Ligurian, Celtic and "Italic" population^{[citation needed]} (such as the Golasecca culture [2]) strata with Gaulish tribes who had come from what is now southern France.

The Insubres are mentioned by Cicero, Polybius, Livy, Pliny the Elder, Strabo and Caecilius Statius.

Regarding the ethnic origin of the Insubres there are two main theses:

1.The first wants them a Celtic population, resulted from migrations happened in the 7th and 6th century BC of Gaulish Celtic tribes towards North-west Italy and their intermixing with the natives.

2.The second, and the most reliable being supported by archaeological findings and their analysis, wants them as part of the Celtic-Ligurian people.

The Roman historian, Livy, wrote about the Insubres. According to his writings all of Northern Italy (between the northern and western Alpine watershed, the rivers Adda and Oglio at the east and Emilian Apennine to south) suffered in the course of centuries of repeated invasions by Celtic tribes from the region of Gaul. He claimed that before the invasion of the 4th century BC there was a previous one, dated around the late 7th and early 6th century BC.