The helmet type Montefortino starts his triumph from the early fourth century B.C. Meanwhile, the origin of the type is supposed to be Celtic. Due to Celtic attacks in the Po Valley and the Picenum, Montefortino helmets appeared in northern Italy already at the beginning of the 4th century B.C. Shortly thereafter the new type of helmet is already being imitated in Etruscan workshops, while this new Etruscan-Italian type is significantly different from the Celtic exemplars. The large majority of the Etruscan-Italian Montefortino helmets of the fourth century B.C. come from the burial grounds of Etruria. The wide spreading of the Italian-Roman exemplars from the 3rd century B.C., especially the findings in rivers and the sea give proof of Rome’s military efforts, primarily between river Po and Adda. As of the second century B.C. the Montefortino type, already strongly modified, is considered to be the standard helmet of the Roman army. It is spread from Spain to the Black Sea.
This helmet corresponds to the sub-type Cremona. The fact that due to the patina this is clearly a finding from a river supports the assumption that the find spot of this helmet is between Po and Adriatic Sea, just like most of the previously known exemplars of the Cremona type, and was worn by a Roman legionnaire during the armed conflicts there with the Celts. The battle of Clastidium would be conceivable. The battle of Clastidium in the year 222 B.C. in the course of Rome’s Celtic wars in Upper Italy ended with a victory of the Romans, who brought the region of the so-called Gallia Cisalpina, i.e. the Po Valley, under their domination. Battles between Romans and Celts were in the Po Valley already 223 B.C
The most important combatants of the Romans was the tribe of the Insubres under their leader Viridomarus with their main location in Mediolanum, today’s Milan. These were able to defeat an initial crossing of the Romans towards the left banks of river Po, however the Romans succeeded in getting the support of the neighbouring Celtic Cenomans and expand into the region of the Insubres. Due to an adverse omen the Roman consul Gaius Flaminius had been ordered back, however he refused to follow this order and referred to his success against the Celts.
The decision followed in the year 222 B.C., when Roman troops again attacked along river Po, this time under the command of Marcus Claudius Marcellus. The crucial battle was finally fought at the southern banks near Clastidium (today‘s Casteggio near Voghera). The Insubrian leader Viridomarus died during the battle; according to the sources he was killed by Marcellus himself, who received the Spolia opima in exchange. The Romans could settle in Milan and thus created a pediment of strategic importance with the Gallia Cisalpina. The Germanic tribes were first mentioned in list of triumphs dated 222 B.C. However, this evidence is disputed in research, since it can also be a late circumscription in the scope of the Augustean compilation of triumphs.
The domination of the Romans over this territory was threatened by the attack of Hannibal at the beginning of the Second Punic War only four years later, but the Roman victory over Carthage and the subsequent abolition of Celtic insurrectionists ensured the suzerainty over the territories captured after the victory of Clastidium.