When the Etruscan power in Latium collapsed after the Latin revanche and the battle of Aricia, the Latins naturally came into conflict with Rome, the most southerly outpost of Etruria. Yet clearly it was to their mutual advantage that ties of blood should prevail and that Rome should once again become the spearhead of the Latins, thrust into the Etruscan flank. Amid the dim mists of legends which envelop this period two facts emerge clearly: that a war was fought between Rome and the Latins, and that it ended in an alliance.1
The earliest treaty between Rome and Carthage shows clearly that Republican Rome claimed to uphold the hegemony in Latium which her kings had exercised. The Latins, however, refused to tolerate this and organized themselves into a league from which Rome was excluded. The identification and development of the early federations of Latins, as has been seen (p. 35), is an obscure subject. One federation met at the nemus Aricinum; a list of members, preserved by Cato who perhaps saw the inscription which he records, shows us that it once was led by a dictator Laevius (or Baebius) Egerius of Tusculum and included Tusculum, Aricia, Lanuvium, Lavinium, Cora, Tibur, Pometia and Ardea, an area of some 600 square miles. It quite probably should be identified with a league which met at Aqua Ferentina, in which Aricia played a leading part in the time of Tarquinius Superbus (Livy, i, 50). However that may be, the Latins probably gathered ad caput Ferentinae to agree their plans for war against Rome. The allied forces then met the Romans at the battle of Lake Regillus (probably Pantano Secco) near Tusculum (499 or 496). Although tradition enlivens the fray with the presence of the Great Twin Brethren and other romantic episodes, the battle itself remains an historical fact, though it was hardly a glorious Roman victory.2
As a result a treaty was concluded by Spurius Cassius in 493 between Rome and thirty Latin cities as two independent powers. Rome formally resigned any claim to hegemony in Latium and recognized her position as an equal of the Latins. The Latins were willing to conclude an agreement, not because of any fictitious military disaster, but the Volsci and Aurunci were pressing hard upon them and had perhaps recently destroyed two Latin cities, Cora and Pometia. It was essential that the Latins should present a united front against their foes. The terms of this treaty, the foedus Cassianum, were that perpetual peace should be established between Rome and the Latins; they should render mutual aid in war and have equal shares of the booty; possibly the military command should be held in alternate years by Rome and the League; further, there should be a community of private rights between citizens of Rome and any Latin city. This last clause is of fundamental importance as it lays down the principle by which Rome ultimately united Italy. The Cassian treaty, of which a bronze copy survived in the Roman Forum till Sulla’s day, remains a landmark in the early history of Rome.3
Soon after the Latin alliance Rome concluded a similar treaty with the Hernici of the Trerus valley, who formed a league under the leadership of Anagnia.4 The traditional details of the alliance are uncertain; it is unlikely that the Hernici obtained the treaty by surrendering some of their territory to Rome, while its similarity to the foedus Cassianum explains why it also was attributed to Spurius Cassius. But its object is clear: the Hernici were saved from being crushed between the Aequi and Volsci, and the Romans by an early application of the principle of divide et impera won a buffer state between their enemies.
This triple alliance of the Romans, Latins and Hernici resulted from a pressing danger. At the beginning of the fifth century the Sabellian tribes of the central Apennines became restless, possibly under the first stirrings of Celtic pressure from the north. Following their tribal emblems, the wolf, bull or boar, the bands of the Sacred Spring were ever advancing to settle in new territories and coveting the fertile lowlands where they saw good winter pasturage for their herds. Their strongest thrust was in southern Italy, but they also pressed hard upon the inhabitants of the mountains that encircle Latium. These in turn presented a grave danger to the Latins. The external history of Rome during the fifth century is the story of how she and her allies had to fight for their very existence against this foreign pressure. For Rome was ringed around by foes. In the north were the Etruscans; in the north-east between the Tiber and Anio were the Sabines from around Reate; in the east among the mountains between the Anio and Trerus lay the Aequi; and in thesouth between the Aequi and the sea on the bastion of Monti Lepini were the Volsci. In the nick of time Rome patched up her quarrel with the Latins by a timely self-effacement and then drove a wedge between two of her enemies by the Hernican alliance.