The Erechtheion or Erechtheum (/ɪˈrɛkθiəm, ˌɛrɪkˈθiːəm/; Ancient Greek: Ἐρέχθειον, Modern Greek:Ερέχθειο) is an ancient Greek temple on the north side of the Acropolis of Athens in Greece which was dedicated to both Athena and Poseidon.