Telos was the son of Helios and Halia, the sister of the Telchines. He came to the island in search of herbs to heal his ill mother, and later returned to found a temple to Apollo and Neptune. However, Telos (Telo or Tilo) does not appear in Greek mythology and the name probably has an unknown pre-Hellenic origin. Pliny the Elder notes that in antiquity Telos was known as Agathussa (Αγαθούσσα) (also Agathusa and Agathousa). In the Middle Ages, it was known by the Italian as Episcopio, either because it was a Bishop Seat or because its position as Vantage Point. The island has also been called in Turkish İlyaki and in modern Italian Piscopi.