The Tiber or Tiberis, formerly called Thybris, and previously Albula[1265], flows down from nearly the central part of the chain of the Apennines, in the territory of the Arretini. It is at first small, and only navigable by means of sluices, in which the water is dammed up and then discharged, in the same manner as the Timia[1266] and the Glanis, which flow into it; for which purpose it is found necessary to collect the water for nine days, unless there should happen to be a fall of rain. And even then, the Tiber, by reason of its rugged and uneven channel, is really more suitable for navigation by rafts than by vessels, for any great distance. It winds along for a course of 150 miles, passing not far from Tifernum[1267], Perusia, and Ocriculum[1268], and dividing Etruria from the Umbri[1269] and the Sabini[1270], and then, at a distance of less than sixteen miles from the city, separating the territory of Veii from that of Crustuminum, and afterwards that of the Fidenates and of Latium from Vaticanum. Below its union with the Glanis from Arretinum the Tiber is swollen by two and forty streams, particularly the Nar[1271] and the Anio, which last is also navigable and shuts in Latium at the back; it is also increased by the numerous aqueducts and springs which are conveyed to the City. Here it becomes navigable by vessels of any burden which may come up from the Italian sea; a most tranquil dispenser of the produce of all parts of the earth, and peopled and embellished along its banks with more villas than nearly all the other rivers of the world taken together. And yet there is no river more circumscribed than it, so close are its banks shut in on either side; but still, no resistance does it offer, although its waters frequently rise with great suddenness, and no part is more liable to be swollen than that which runs through the City itself. In such case, however, the Tiber is rather to be looked upon[1272] as pregnant with prophetic warnings to us, and in its increase to be considered more as a promoter of religion than a source of devastation. Latium[1273] has preserved its original limits, from the Tiber to Circeii[1274], a distance of fifty miles: so slender at the beginning were the roots from which this our Empire sprang. Its inhabitants have been often changed, and different nations have peopled it at different times, the Aborigines, the Pelasgi, the Arcades, the Seculi, the Aurunci, the Rutuli, and, beyond Circeii, the Volsci, the Osci, and the Ausones whence the name of Latium came to be extended as far as the river Liris[1275].