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.