The main oracle centers of the Greeks were established at particular geodetic locations, marking latitude lines. Dodona, Delphi, and Delos are one degree apart (39簞 30', 38簞 30', 37簞 30') in succession. In classical antiquity, an oracle was a person or agency considered to provide wise and insightful counsel or prophetic predictions or precognition of the future, inspired by the gods. As such it is a form of divination. The most important oracles of Greek antiquity were Pythia, priestess to Apollo at Delphi, and the oracle of Dione and Zeus at Dodona in Epirus. Other temples of Apollo were located at Didyma on the coast of Asia Minor, at Corinth and Bassae in the Peloponnese, and at the islands of Delos and Aegina in the Aegean Sea. The Sibylline Oracles are a collection of oracular utterances written in Greek hexameters ascribed to the Sibyls, prophetesses who uttered divine revelations in frenzied states.