In process of time the ancient Servian phalanx had been superseded by an admirably organised and mobile disposition of the troops in maniples of 160 men each. Ranged in three files, with lateral spaces between, these bodies relieved one another during the fight, and thus were able to quell the most vehement onslaught of the enemy by constantly bringing forward fresh troops, which first hurled their long javelins and then charged with their short swords.
It became more and more the practice of the Roman state to extend to the lower classes the obligation of military service, which in all other parts of Italy was a privilege of the assidui or freeholders. Large numbers of landless men and freedmen were enrolled in the recruiting districts (tribus) in war times by the famous censor Appius Claudius Cæcus.
Opportune political changes favoured the development of Roman supremacy in Italy. The Etruscan dominion had fallen into utter decay during the course of the fifth century. Rome’s victorious struggle for liberty, the advance of the Samnites in southern Italy, and the immigration of the Gauls into northern Italy, had reduced Etruria to a second-class power. In the south the power of the wealthy Greek cities had been broken by Dionysius of Syracuse. Step by step Roman colonists made their way into lower Italy. Where the sword was of no avail Rome had recourse to road-making, the occupation and cultivation of waste land, and fresh settlements. Above all, the Latin colonies which she established in concert with the Latin league were of the utmost importance in securing the supremacy of Rome in middle Italy. These colonies served as fortresses, the colonists were a garrison always ready to stand on the defensive. The colonies themselves were established in such a way as to obstruct the coalition of the various races of Italy. They spread abroad Latin law and the Latin language among foreigners. They once more united the Romans and Latins in a common work of civilisation, after the two peoples had so hotly fought against each other in what is known as the Great Latin War (340-338 B.C.).
The skilful diplomatic negotiations and settlements by which Rome contrived either to gain over her former adversaries or reduce them to neutrality before she engaged in the struggle with the Samnites for the hegemony of Italy (342-340 and 326-304) are particularly worthy of note. She protected her rear by concluding armistices for many years with the Etruscans (351-311) and Gauls (329-299). She entered into friendly relations with the Greek cities, and won over many communities in Campania and Lucania which had put themselves under the protection of the Samnites. Nay, she did not shrink from purchasing the friendship of Carthage by allowing her to take and plunder the seaboard cities of middle Italy which had revolted against Roman dominion. And she further displayed remarkable skill in securing her tenure of the possessions won in the Samnite wars. Only a small part of them was incorporated with Roman territory. Many cities received an accession of Latin colonists and so retained their municipal autonomy under new conditions. On the other hand the connection between the recalcitrant cantons of the Sabellian, Etruscan, and Middle Italian tribes was completely broken. Isolated and deprived of the right of intercourse (commercium) the various small cities and communities ceased to be of any importance either economically or politically.
The Romans had hardly completed the conquest of Etruria and the Samnite confederacy in the Third Samnite War (298-290 B.C.), and subjugated the kindred districts of Lucania and Bruttium when they found themselves involved in the struggles which then agitated the Greek world.
After 301 the several parts of the empire of Alexander the Great had become independent kingdoms. But the quarrels among the various diadochi went on and ultimately led to the expulsion of Demetrius Poliorcetes from Macedonia and the fall of Lysimachus of Thrace.
The unsettled state of these kingdoms inspired hordes of Gauls, athirst for plunder, with the idea of crossing the Alps and conquering both the Apennine and Balkan peninsulas. Italy owed her salvation to the vigorous defence made by the Romans at the Vadimonian Lake (283 B.C.); but Macedonia was occupied for several years and the swarms of Gauls spread as far as Delphi, and finally settled in Asia Minor under the name of Galatians.
Even before the Gallic invasion, Pyrrhus of Epirus, who had taken possession of Macedonia for a while, had withdrawn to his own home, and he and his army of mercenaries turned their eyes westward, eager for action. The wished-for opportunity of there regaining the influence and reputation he had lost in the west was not slow to present itself. Tarentum, the last independent city of any importance in Italy, had provoked Rome to hostilities and was endeavouring to enlist mercenaries for the war. Pyrrhus went to the help of the Tarentines, even as Alexander of Epirus, a cousin of Alexander the Great, had gone before him (334 B.C.). After some initial successes the latter had lost his life in battle against the Lucanians (331 B.C.). His nephew did not fare much better. The generalship of Roman mayors, elected afresh every year, was at first no match for that of Pyrrhus, who had great military successes to look back upon. Up to this time the Macedonian phalanx had invariably proved the instrument of victory, especially in the opening encounters of a campaign, and even the men of Rome gave ground before the elephants, the “heavy artillery” of the Epirots. But the second victory which the king gained over the Romans was a “Pyrrhic victory,” for his gains did not compensate his losses. On this occasion Rome owed the victory mainly to the inflexible courage of her statesmen. The blind Appius Claudius, who thirty years before had borne an honourable part in the successful struggle with the Samnites, caused himself to be led into the senate and by his arguments induced the Romans inflexibly to refuse all offers of peace on less than favourable terms. “Never have the Romans concluded peace with a victorious foe.” These proud words contain the secret of the ultimate success of Rome in all her wars of that century.
Fortunately for the Romans, at that very time the Greeks of Sicily urgently craved the aid of the king of Epirus. They had been defeated by the Carthaginians and their independence was menaced. Pyrrhus accordingly departed from Italy for more than two years, to gain some initial successes in Sicily and end in failure. When he returned to Italy it was too late. The Romans had established their dominion over the Italian rebels and were once more harassing Tarentum. Pyrrhus suffered a disastrous defeat at Beneventum in Samnium (275 B.C.), and Tarentum submitted soon after (272 B.C.). Pyrrhus himself was slain in Greece about the same time.