Rome was at that time ruled by kings, assisted by a council of the elders of the city (the hundred senators). In important affairs they had to obtain the assent of the popular assembly (comitia curiata) which voted in thirty curiæ, according to the number of the thirty places of sacrifice in the city. For the rest, the kings had a tolerably free hand in the appointment of magistrates and priests.
From the legendary details of the history of the monarchy one thing only is clear, to wit, that in the sixth century B.C. Rome was ruled by monarchs of Etruscan descent and was to some extent a dependency of the Etruscan rulers of the period.
In the seventh and sixth centuries B.C. the Etruscans had both vigorously repulsed the invasions of the Sabellians and taken the offensive on their own account. They had not only maintained and increased their dominion in the valley of the Po, but had established the Tuscan League of the Twelve Cities in Umbria, and thus put an end to Umbrian independence. At this time their sway extended southwards as far as Campania. A Tuscan stronghold (Tusculum) was built on the Alban hills. Etruscan sources of information, and first and foremost the pictures in Tuscan sepulchral chambers, leave no room to doubt that the Etruscan descent of the last three kings of Rome, the Tarquins and Servius Tullius, is a historic fact. Rome was therefore involved in the military operations of Etruscan commanders “Lucumones,” who fortified the city, adorned it with temples and useful buildings (among others the famous cloaca maxima, the first monument of vaulted architecture on Roman soil), and reorganised the army by the introduction of the Servian system of centuries, which afterwards became the foundation-stone of the Roman constitution. The whole body of the people was divided into four urban and sixteen rural recruiting districts (tribus), and all freeholders (assidui) were laid under the obligation of military service on the basis of a property qualification. Classes I to III served as heavy-armed soldiers, classes IV and V as light-armed. The whole number together constituted a body of 170 companies (170 × 100), divided into two legions on the active list and two in reserve, each 4200 strong, or 193 centuries inclusive of the centuries of mounted troops. From the establishment of the republic onwards this army was called together to elect consuls and vote upon laws under the title of the comitia centuriata.
The municipal comitia curiata ceased to be politically effective first under the military despotism of foreign rulers and then by reason of the expansion of the state till it included an area of nearly a thousand square kilometres. From that time forward the tribus became the basis of all political organisation, and remained so to the end.
But the army thus reorganised was a two-edged weapon. The tyrannical license of the last Tarquin roused the love of liberty in the breasts of the Romans. The army renounced its allegiance; through years of conflict and in sanguinary battles Rome, and all Latium with her, won back its independence of foreign Tuscan rulers.
The wars waged by Rome in the century after the expulsion of the kings are hardly worthy to be recorded on the roll of history. After valiantly repulsing the Etruscan commanders who endeavoured to restore Tarquin (496 B.C., battle of Lake Regillus), Rome entered into a permanent alliance with the Latin confederacy, an alliance that was not only strong enough to protect her against the constant attacks of mountain tribes (Æquians and Sabines on the northeast and Volscians on the southeast) but enabled her gradually to push forwards and conquer the south Etruscan cities of Veii and Fidenæ. Fidenæ fell in the year 428 B.C., Veii the emporium of southern Etruria, was reduced in 396, after a siege of ten years’ duration.
An attempt to intermeddle in the affairs of northern Etruria resulted in a catastrophe that threatened Rome with final annihilation. Some time earlier hordes of Gauls had penetrated into northern Italy through the passes of the Alps. At the beginning of the fourth century B.C. the Senonian Gauls effected a permanent settlement in the valley of the Po and from thence invaded Etruria. When they attacked Clusium (Chiusi) in middle Etruria the Romans made an attempt at diplomatic intervention, but only succeeded in diverting the wrath of the enemy to themselves. The Gauls made a rapid advance, succeeded in routing the Roman forces at the little river Allia, only a few miles from Rome, and occupied the city itself. The citadel alone held out, but more than six months elapsed before the flood of barbarians subsided, and Rome was forced to purchase peace by humiliating concessions.
Rome arose after her fall with an energy that commands admiration, and she had soon won a position in middle Italy more important than that which she had held before the Gallic invasion. By partitioning southern Etruria among Roman citizens and founding colonies which at the same time served as fortresses and substantial bases for the advance of the Roman army she became a power of such consequence that she not only compelled the Æquians and Volscians by degrees to acknowledge her suzerainty but was able to assume the offensive in middle Etruria and the land of the Sabines.
When the Senonian Gauls returned to the attack, as they did two or three times a generation later (360, 349, and 330 B.C.), they found themselves confronted by the forces of the Latin league in such numbers that they declined to join issue in a pitched battle, presently retreated, and finally concluded a truce for thirty years (329-299 B.C.).
The increased strength of the Roman community within its own borders after the catastrophe of the Gauls is vouched for by the multiplication of municipal districts in spite of heavy losses in the field, the number and importance of the colonies, the gradual expansion of commerce and augmentation of the mercantile marine, the introduction of coined money (about 360 B.C.) in place of the clumsy bars of copper, and lastly, the increasingly active relations of Rome with foreign powers. About the year 360 B.C. the Romans sent votive offerings to Delphi, and made efforts both before and after to introduce Greek cults into their own country. But the strongest evidence of the extension of Roman trade and the esteem in which Rome was held as the contract-making capital of the commercial cities of middle Italy is furnished by her treaties with Carthage (probably 348 and 343 B.C.). The provisions (the text of which has come down to us) that Roman vessels should not sail westwards beyond a certain line in north Africa or in Spain, prove conclusively that the Carthaginians thought Italico-Roman competition a thing worth taking into account.