Thourioi , Thurii or Thurium was a city of the Grande Greece on the Golfe of Tarente, close to the ancient site of Sybaris. The foundation of the city went back to 452 av. J.C, and was the work of exiled of Sybaris and their descendants which wished to repopulate the site of the antique Sybaris.

A panhellenic colony is founded between 446 and 443 av. J. - C., on the ruins of old the Sybaris, on plans of Hippodamos. This colony is resulting from the foreign policy of Périclès, during one period of Athenian imperialism. The colonists are originating in the cities of the Aegean Sea then under domination of Athens through the league of Délos. The Panhellénisme of this colony must thus be called in question. For example, the Spartans refused to send colonists to Thourioi. The Corinthians react to this colonization which threatens their interests.

Took part in particular in this colonization the historian Hérodote, the speaker Lysias and Hippodamos de Milet. The tradition wants in particular that the famous Sophiste Protagoras wrote the code of laws of this city. Diodore of Sicily describes us this city.