The militia of the Etruscans and Sabines was to occupy the Apennines and if possible to obstruct the passage, till the regular troops could arrive.

A reserve was formed in Rome of 50,000 men.
Throughout all Italy, which on this occasion recognized its true champion in Rome, the men capable of service were enrolled, and stores and materials of war were collected.
Battle of Telamon All this, however, required time.

For once the Romans had allowed themselves to be surprised, and it was too late at least to save Etruria.

The Celts found the Apennines hardly defended, and plundered unopposed the rich plains of the Tuscan territory, which for long had seen no enemy.

They were already at Clusium, three days' march from Rome, when the army of Ariminum, under the consul Papus, appeared on their flank, while the Etruscan militia, which after crossing the Apennines had assembled in rear of the Gauls, followed the line of the enemy's march.