Tiber River. The Tiber is the third-longest river in Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing 406 kilometres through Tuscany, Umbria and Lazio, where it is joined by the river Aniene, to the Tyrrhenian Sea, between Ostia and Fiumicino. It drains a basin estimated at 17,375 square kilometres. The river has achieved lasting fame as the main watercourse of the city of Rome, founded on its eastern banks. The river rises at Mount Fumaiolo in central Italy and flows in a generally southerly direction past Perugia and Rome to meet the sea at Ostia. Popularly called flavus, in reference to the yellowish colour of its water, the Tiber has heavily advanced at the mouth by about 3 kilometres since Roman times, leaving the ancient port of Ostia Antica 6 kilometres inland. However, it does not form a proportional delta, owing to a strong north-flowing sea current close to the shore, to the steep shelving of the coast, and to slow tectonic subsidence. The source of the Tiber consists of two springs 10 metres away from each other on Mount Fumaiolo. These springs are called Le Vene. The springs are in a beech forest 1,268 metres above sea level. During the 1930s, Benito Mussolini placed an antique marble Roman column at the point where the river arises, inscribed. There is an eagle on the top of this column. The first miles of the Tiber run through Valtiberina before entering Umbria. According to legend, the city of Rome was founded in 753 BC on the banks of the Tiber about 25 kilometres from the sea at Ostia. Tiber Island, in the center of the river between Trastevere and the ancient city center, was the site of an important ancient ford and was later bridged. Legend says Rome's founders, the twin brothers Romulus and Remus, were abandoned on its waters, where they were rescued by the she-wolf, Lupa. The river marked the boundary between the lands of the Etruscans to the west, the Sabines to the east and the Latins to the south. Benito Mussolini, born in Romagna, adjusted the boundary between Tuscany and Emilia-Romagna, so that the springs of the Tiber would lie in Romagna. The Tiber was critically important to Roman trade and commerce, as ships could reach as far as 100 kilometres upriver; there is evidence that it was used to ship grain from the Val Teverina as long ago as the 5th century BC. It was later used to ship stone, timber and foodstuffs to Rome. During the Punic Wars of the 3rd century BC, the harbour at Ostia became a key naval base. It later became Rome's most important port, where wheat, olive oil, and wine were imported from Rome's colonies around the Mediterranean. Wharves were also built along the riverside in Rome itself, lining the riverbanks around the Campus Martius area. The Romans connected the river with a sewer system and with an underground network of tunnels and other channels, to bring its water into the middle of the city. Wealthy Romans had garden-parks or horti on the banks of the river in Rome up through the first century BC. These may have been sold and developed about a century later. The heavy sedimentation of the river made it difficult to maintain Ostia, prompting the emperors Claudius and Trajan to establish a new port on the Fiumicino in the 1st century AD. They built a new road, the via Portuensis, to connect Rome with Fiumicino, leaving the city by Porta Portese. Both ports were eventually abandoned due to silting. Several popes attempted to improve navigation on the Tiber in the 17th and 18th century, with extensive dredging continuing into the 19th century.