The Tiber (Latin Tiberis, Italian Tevere, Italian pronunciation: is the third-longest river in Italy, rising in the Apennine mountains in Emilia-Romagna and flowing 406 kilometres (252 mi) through Umbria and Lazio to the Tyrrhenian Sea. It drains a basin estimated at 17,375 square kilometres (6,709 sq mi). The river has achieved lasting fame as the main watercourse of the city of Rome, founded on its eastern banks.
It is probable that the name Tiber is pre-Latin, like the Roman name of Tibur (modern Tivoli). It may be Etruscan or Italic in origin, possibly akin to the Celtic root-word dubr, "water". The same root is believed to be the source of the Latin praenomen Tiberius, and its Etruscan cognate, Thefarie.
The legendary king Tiberinus Silvius, or Thebris, ninth in the king-list of Alba Longa, was said to have drowned in the Albula River, which was subsequently renamed in his honour. The myth may have explained a memory of an earlier, perhaps pre-Indo-European name for the river, "white" (alba) with sediment. According to the legend, Jupiter made him a god and guardian spirit of the river (also called Volturnus, "rolling water"). This gave rise to the standard Roman depiction of the river as a powerfully built reclining river god, also named Tiberinus, with streams of water flowing from his hair and beard. The River Tiber was also believed to be the river into which Romulus and Remus (the former founded Rome) were thrown as infants.