Latium was originally a small triangle of fertile, volcanic soil (Latium vetus) on which resided the tribe of the Latins or Latians. It was located on the left bank (east and south) of the River Tiber, extending northward to the River Anio (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 neighbours, expanding its dominions over Southern Etruria and to the south, in a partly marshy and partly mountainous region. The latter saw the creation of numerous Roman and Latin colonies: small Roman colonies were created along the coast, while the inland areas were colonized by Latins and Romans without citizenship. The name Latium was thus also extended to this area south of Rome (Latium adiectum), up to the city of the ancient Oscan city of Casinum, defined by Strabo as "the last city of the Latins".