Latium (, ) is the region of central western Italy in which the city of Rome was founded and grew to be the capital city of the Roman Empire. Latium was originally a small triangle of fertile, volcanic soil on which resided the tribe of the Latins or Latians. It was located on the left bank (east and south) of the Tiber river, extending northward to the Anio river (a left-bank tributary of the Tiber) and southeastward to the Pomptina Palus (Pontine Marshes, now the Pontine Fields) as far south as the Circeian promontory. The right bank of the Tiber was occupied by the Etruscan city of Veii, and the other borders were occupied by Italic tribes. Subsequently Rome defeated Veii and then its Italic neighbors, expanding Latium to the Apennine Mountains in the northeast and to the opposite end of the marsh in the southeast. The modern descendant, the Italian Regione of Lazio, also called Latium in Latin, and occasionally in modern English, is somewhat larger still, but not as much as double the original Latium.