The six years of peace which followed (304-298) were em ployed by Rome in still further strengthening her position. Al ready, two years before the peace, a rash revolt of the Hernici had given Rome a pretext for finally annexing the territory of her ancient allies. The tribal confederacy was broken up, and all the Hernican communities, with the exception of three which had not joined the revolt, were incorporated with the Roman State as municipia, with the civil rights of the Roman franchise. Be tween the Hernican valley and the frontiers of the nearest Sabellian tribes lay what remained of the once formidable people of the Aequi. In their case, too, a revolt (3o4) was followed by the annexation of their territory, which was marked in this case by the formation there (3o1) of two Roman tribes (Aniensis and Teretina). Not content with thus carrying the borders of their own territory up to the very frontiers of the Sabellian country, Rome succeeded (304) in finally detaching from the Sabellian confederacy all the tribes lying between the north-east frontier of Latium and the Adriatic sea. Henceforward the Marsi, Paelig ni, Vestini, Marrucini and Frentani were enrolled among the allies of Rome, and not only swelled her forces in the field but interposed a useful barrier between her enemies to the north in Etruria and Umbria and those to the south in Samnium, while they connected her directly with the friendly Apulians. Lastly, as a security for the fidelity at least of the nearest of these allies, colonies were planted in the Marsian territories at Alba Fucentia (303) and at Carsioli (298). A significant indication of the widen ing range of Rome's influence in Italy, and of the new responsi bilities rapidly pressing upon her, is the fact that when in 302 the Spartan Cleonymus landed in the territory of the Sallentini, far away in the south-east, he was met and repulsed by an Italic and Roman force.
Third Samnite War.—Six years after the conclusion of the treaty which ended the second Samnite War, news arrived that the Samnites were harassing the Lucanians. Rome at once inter fered to protect her allies. Samnium was invaded in force, the country ravaged and one stronghold after another captured. Unable any longer to hold their own in a position where they were hedged round by enemies, the Samnite leaders turned as a last hope to the communities of northern Etruria, to the free tribes of Umbria and to the once dreaded Celts. With a splendid daring they formed the scheme of uniting all these people with themselves in a last desperate effort to break the power of Rome.
For some 4o years after the final annexation of southern Etruria (351 B.c.) matters had remained unchanged in that quar ter. Sutrium and Nepete still guarded the Roman frontier; the natural boundary of the Ciminian forest was still intact ; and up the valley of the Tiber, Rome had not advanced beyond Falerii, a few miles short of the most southerly Umbrian town Ocriculum. But in 311, on the expiry, apparently, of the long truce with Rome, concluded in 351, the northern Etruscans, alarmed no doubt by the rapid advances which Rome was making farther south, rose in arms and attacked Sutrium. The attack, however, recoiled disastrously upon the heads of the assailants. A Roman force promptly relieved Sutrium, and its leader, Q. Fabius
Rullianus, without awaiting orders from home, boldly plunged into the wilds of the Ciminian forest, and crossing them safely swept with fire and sword over the rich lands to the north. Then turning southwards he met and utterly defeated the forces which the Etruscans had hastily raised in the hopes of intercepting him at the Vadimonian lake. This decisive victory ended the war. The Etruscan cities, disunited among themselves, and enervated by long years of peace, abandoned the struggle for the time, paid a heavy indemnity and concluded a truce with Rome (3o9–o8). In the same year the promptitude of Fabius easily averted a threatened attack by the Umbrians, but Rome proceeded never theless to fortify herself in her invariable fashion against future dangers on this side, by an alliance with Ocriculum, which was followed ten years later (299) by a colony at Narnia, and an alliance with the Picentes, whose position in the rear of Umbria rendered them as valuable to Rome as the Apulians had proved farther south.
Fourteen years had passed since the battle on the Vadimonian lake, when the Samnites appeared on the borders of Etruria and called on the peoples of northern Italy to rise against the corn mon enemy. Their appeal, backed by the presence of their troops, was successful. The Etruscans found courage to face the Roman legions once more; a few of the Umbrians joined them; but the most valuable allies to the Samnites were the Celts, who had for some time threatened a raid across the Apen nines, and who now marched eagerly into Umbria and joined the coalition. The news that the Celts were in motion produced a startling effect at Rome, and every nerve was strained to meet this new danger. While two armies were left in southern Etruria as reserves, the two consuls, Q. Fabius Maximus Rullianus and P. Decius Mus the younger, both tried soldiers, marched north wards up the valley of the Tiber and into Umbria at the head of f our Roman legions and a still larger force of Italian allies. At Sentinum, on the farther side of the Apennines, they encountered the united forces of the Celts and Samnites, the Etruscans and Umbrians having, it is said, been withdrawn for the defence of their own homes. The battle that followed was desperate, and the Romans lost one of their consuls, Decius, and more than 8,000 men. But the Roman victory was decisive. The Celts were annihilated, and the fear of a second Celtic attack on Rome removed. All danger from the coalition was over. The Etruscan communities gladly purchased peace by the payment of indem nities. The rising in Umbria, never formidable, died away, and the Samnites were left single-handed to bear the whole weight of the wrath of Rome. During four years more, however, they desperately defended their highland homes, and twice at least, in 293 and 292, they managed to place in the field a force suffi cient to meet the Roman legions on equal terms. At last, in 29o, the consul M. Curius Dentatus finally exhausted their power of resistance. Peace was concluded, and it is significant of the respect inspired at Rome by their indomitable courage that they were allowed to become the allies of Rome, on equal terms and without any sacrifice of independence.