called
the Gasatae, crossed the Alps and, joined by the Boii and Insubres,
prepared to invade Roman territory with a force of 50,000 foot and 20,000
mounted men. The Romans and Italians were seriously alarmed, for the
memory of the fatal day of the Allia had never been effaced. Rome called
for a military census of her whole federation. The lists showed 700,000
infantry and 70,000 cavalry. Expecting the Gauls to advance into Umbria
the Romans stationed an army under one consul at Ariminum. The other
consul was sent to Sardinia, possibly from fear of a Carthaginian attack,
while the defence of Etruria was left to a force of Roman allies.
Alliances were concluded with the Cenomani, a Gallic tribe to the north of
the Po, and with the Veneti.

Avoiding the army at Ariminum the Gauls crossed the Apennines into
Etruria, defeated the Roman allies and plundered the country. But the
consul from Ariminum hastened to the rescue, the army in Sardinia was
recalled, and the Gauls began to withdraw northwards to place their spoils
in safety. The Romans followed and as the army from Sardinia landed to the
north of the foe and cut off their retreat, the latter were surrounded and
brought to bay at Telamon. They were annihilated in a bloody battle won by
the superiority of the Roman tactics and generalship. One of the Roman
consuls fell on the field of battle.

*War against the Boii and Insubres: 224-222 B. C.* Italy was saved, and
now the Romans decided to expel the Boii and the Insubres from the Po
valley as a penalty for their conduct and to prevent future invasions of
this sort by occupying their territory. In three hard-fought campaigns the
Romans, while they failed to exterminate or dispossess these peoples,
reduced them to subjection, forcing them to surrender part of their
territory and to pay tribute. But the Romans did not conquer without
suffering heavy losses, and their ultimate success was to a considerable
degree due to the cooeperation of the Cenomani.

*The Roman frontier reaches the Alps.* Between 221 and 219 the Romans
subdued the peoples of the Adriatic coast as far as the peninsula of
Istria. Thus, with the exception of Liguria and the upper valley of the
Po, all Italy to the south of the Alps was brought within the sphere of
Roman influence. The Latin colonies Placentia and Cremona were founded in
the territory taken from the Insubres to secure the Roman authority in
this region, but Hannibal's invasion of 217 B. C