The ancient site of Dodona is located 22 km. south of Ioannina, in the narrow valley between the mounts Tomaros and Manoliassa. The first remains on the site date from the prehistoric period and the first deity worshipped here was the Earth goddess. The cult of Zeus and the sacred oak tree was brought to Dodona by the Selloi, a branch of the Thesprotian tribe, between the 19th and 14th centuries B.C. and soon became the prevalent cult of the sanctuary.