In the same year, in which Tarentum became Roman, the Samnites, Lucanians, and Bruttians finally submitted. The latter were obliged to cede the half of the lucrative, and for ship-building important, forest of Sila.

At length also the band that for ten years had sheltered themselves in Rhegium were duly chastised for the breach of their military oath, as well as for the murder of the citizens of Rhegium and of the garrison of Croton. In this instance Rome, while vindicating her own rights vindicated the general cause of the Hellenes against the barbarians. Hiero, the new ruler of Syracuse, accordingly supported the Romans before Rhegium by sending supplies and a contingent, and in combination with the Roman expedition against the garrison of Rhegium he made an attack upon their fellow-countrymen and fellow-criminals, the Mamertines of Messana. The siege of the latter town was long protracted.  On the other hand Rhegium, although the mutineers resisted long and obstinately, was stormed by the Romans in 484; the survivors of the garrison were scourged and beheaded in the public market at Rome, while the old inhabitants were recalled and, as far as possible, reinstated in their possessions. Thus all Italy was, in 484, reduced to subjection. The Samnites alone, the most obstinate antagonists of Rome, still in spite of the official conclusion of peace continued the struggle as "robbers", so that in 485 both consuls had to be once more despatched against them. But even the most high-spirited national courage - the bravery of despair - comes to an end; the sword and the gibbet at length carried quiet even into the mountains of Samnium.

For the securing of these immense acquisitions a new series of colonies was instituted: Paestum and Cosa in Lucania (481); Beneventum (486), and Aesernia (about 491) to hold Samnium in check; and, as outposts against the Gauls, Ariminum (486), Firmum in Picenum (about 490), and the burgess colony of Castrum Novum. Preparations were made for the continuation of the great southern highway - which acquired in the fortress of Beneventum a new station intermediate between Capua and Venusia - as far as the seaports of Tarentum and Brundisium, and for the colonization of the latter seaport, which Roman policy had selected as the rival and successor of the Tarentine emporium. The construction of the new fortresses and roads gave rise to some further wars with the small tribes, whose territory was thereby curtailed: with the Picentes (485, 486), a number of whom were transplanted to the district of Salernum; with the Sallentines about Brundisium (487, 488); and with the Umbrian Sassinates (487, 488), who seem to have occupied the territory of Ariminum after the expulsion of the Senones. By these establishments the dominion of Rome was extended over the interior of Lower Italy, and over the whole Italian east coast from the Ionian sea to the Celtic frontier.

Before we describe the political organization under which the Italy which was thus united was governed on the part of Rome, it remains that we should glance at the maritime relations that subsisted in the fourth and fifth centuries. At this period Syracuse and Carthage were the main competitors for the dominion of the western waters. On the whole, notwithstanding the great temporary successes which Dionysius (348-389), Agathocles (437-465), and Pyrrhus (476-478) obtained at sea, Carthage had the preponderance and Syracuse sank more and more into a naval power of the second rank.  The maritime importance of Etruria was wholly gone[6]; the hitherto Etruscan island of Corsica, if it did not quite pass into the possession, fell under the maritime supremacy, of the Carthaginians. Tarentum, which for a time had played a considerable part, had its power broken by the Roman occupation. The brave Massiliots maintained their ground in their own waters; but they exercised no material influence over the course of events in those of Italy. The other maritime cities hardly came as yet into serious account.

Rome itself was not exempt from a similar fate; its own waters were likewise commanded by foreign fleets. It was indeed from the first a maritime city, and in the period of its vigour never was so untrue to its ancient traditions as wholly to neglect its war marine or so foolish as to desire to be a mere continental power. Latium furnished the finest timber for ship-building, far surpassing the famed growths of Lower Italy; and the very docks constantly maintained in Rome are enough to show that the Romans never abandoned the idea of possessing a fleet of their own. During the perilous crises, however, which the expulsion of the kings, the internal disturbances in the Romano-Latin confederacy, and the unhappy wars with the Etruscans and Celts brought upon Rome, the Romans could take but little interest in the state of matters in the Mediterranean; and, in consequence of the policy of Rome directing itself more and more decidedly to the subjugation of the Italian continent, the growth of its naval power was arrested. There is hardly any mention of Latin vessels of war up to the end of the fourth century, except that the votive offering from the Veientine spoil was sent to Delphi in a Roman vessel (360). The Antiates indeed continued to prosecute their commerce with armed vessels and thus, as occasion offered, to practise the trade of piracy also, and the "Tyrrhene corsair" Postumius, whom Timoleon captured about 415, may certainly have been an Antiate; but the Antiates were scarcely to be reckoned among the naval powers of that period, and, had they been so, the fact must from the attitude of Antium towards Rome have been anything but an advantage to the latter. The extent to which the Roman naval power had declined about the year 400 is shown by the plundering of the Latin coasts by a Greek, presumably a Sicilian, war fleet in 405, while at the same time Celtic hordes were traversing and devastating the Latin land[7]. In the following year (406), and beyond doubt under the immediate impression produced by these serious events, the Roman community and the Phoenicians of Carthage, acting respectively for themselves and for their dependent allies, concluded a treaty of commerce and navigation - the oldest Roman document of which the text has reached us, although only in a Greek translation[8]. In that treaty the Romans had to come under obligation not to navigate the Libyan coast to the west of the Fair Promontory (Cape Bon) excepting in cases of necessity.  On the other hand they obtained the privilege of freely trading, like the natives, in Sicily, so far as it was Carthaginian; and in Africa and Sardinia they obtained at least the right to dispose of their merchandise at a price fixed with the concurrence of the Carthaginian officials and guaranteed by the Carthaginian community. The privilege of free trading seems to have been granted to the Carthaginians at least in Rome, perhaps in all Latium; only they bound themselves neither to do violence to the subject Latin communities[9], nor, if they should set foot as enemies on Latin soil, to take up their quarters for a night on shore - in other words, not to extend their piratical inroads into the interior - nor to construct any fortresses in the Latin land. We may probably assign to the same period the already mentioned[10] treaty between Rome and Tarentum, respecting the date of which we are only told that it was concluded a considerable time before 472. By it the Romans bound themselves - for what concessions on the part of Tarentum is not stated - not to navigate the waters to the east of the Lacinian promontory; a stipulation by which they were thus wholly excluded from the eastern basin of the Mediterranean.