Latium, one of the principal divisions of ancient Italy. The name is variously derived from Latinus, who more probably owed his to that of the region; from latere, to be hidden; from latus, broad, etc.; but hardly any of the derivations are satisfactory. The boundaries of Latium varied in different periods of Roman history. In the earliest times the name designated a small tract of land S. of the Tiber, inhabited by the Latins; it subsequently extended as far S. as the promontory of Circeii and Anxur or Terracina; and in its latest and widest acceptation it included the lower valley of the Liris, and embraced all the land between the Tiber, the territories of the Sabines and Samnites, Campania, and the Tyrrhenian sea. Pliny calls the southernmost part Latium Adjectum, in contradistinction to Latium Antiquum. The greater part of the whole territory is an undulating plain, gradually rising from the seashore to the Apennines, with an isolated range of mountains, Mt. Albanus, of which Mt. Algidus and the Tusculan hills are branches. A part of the coast land between Antium and Terracina was gradually converted into the Pontine marshes by the waters of various streams which found no outlet; all other parts of Latium were renowned for fertility.

In the vicinity of Campania some of the choicest wines of Italy were produced. Among the towns of Latium conspicuous in the history of Rome we find, besides the eternal city itself, Alba Longa, Lavinium, Antium, Corioli, Ardea, and Tusculum. The most ancient inhabitants of Latium, the Siculi, were expelled by a people of Pelasgic descent, who there became known as Latins, or Prisci Latini, in contradistinction to the later Latin subjects of Rome. They formed a league of 30 cities, of which Alba was subsequently the head. Alba succumbed to Rome, one of its colonies, under Tullus Hostilius, and other Latin towns soon after. Rome entered the league under its sixth king, and became its head under the next and last. On the fall of the Tarquins the Latins regained their independence, and struggled long against the republic to maintain it; but it was finally overthrown by the great victory of the Romans near Mt. Vesuvius (340 B. C). Several of their towns received the Roman franchise, and others were converted into allied towns, under the general name of Nomen Latinum. During their independence, the Latin towns, mostly built on the top of steep and fortified hills, were governed by dictators elected annually, senates, and popular assemblies.

Their common meetings, in which federal questions were discussed, were held in a sacred grove at the foot of Mt. Albanus, on the top of which stood a temple of Jupiter Latiaris. An ancient festival in honor of that divinity was adopted by the Romans, retaining its name of Ferice Latince.