The Temple of Hephaestus or Hephaisteion (also "Hephesteum"; Ancient Greek: Ἡφαιστεῖον, Modern Greek: Ναός Ηφαίστου) or earlier as the Theseion (also "Theseum"; Ancient Greek: Θησεῖον, Modern Greek: Θησείο), is a well-preserved Greek temple; it remains standing largely as built. It is a Doric peripteral temple, and is located at the north-west side of the Agora of Athens, on top of the Agoraios Kolonos hill. From the 7th century until 1834, it served as the Greek Orthodox church of Saint George Akamates. The building's condition has been maintained due to its history of varied use.
Hephaestus was the patron god of metal working, craftsmanship, and fire. There were numerous potters' workshops and metal-working shops in the vicinity of the temple, as befits the temple's honoree. Archaeological evidence suggests that there was no earlier building on the site except for a small sanctuary that was burned when the Persians occupied Athens in 480 BCE. The name Theseion or Temple of Theseus was attributed to the monument under the assumption it housed the remains of the Athenian hero Theseus, brought back to the city from the island of Skyros by Kimon in 475 BCE, but refuted after inscriptions from within the temple associated it firmly with Hephaestus.
After the battle of Plataea, the Greeks swore never to rebuild their sanctuaries destroyed by the Persians during their invasion of Greece, but to leave them in ruins, as a perpetual reminder of the war. The Athenians directed their funds towards rebuilding their economy and strengthening their influence in the Delian League. When Pericles came to power, he envisioned a grand plan for transforming Athens into the centre of Greek power and culture. Construction started in 449 BCE, and some scholars believe the building not to have been completed for some three decades, funds and workers having been redirected towards the Parthenon. The western frieze was completed between 445–440 BCE, while the eastern frieze, the western pediment and several changes in the building's interior are dated by these scholars to 435–430 BCE, largely on stylistic grounds. It was only during the Peace of Nicias (421–415 BCE) that the roof was completed and the cult images were installed. The temple was officially inaugurated in 416–415 BCE.
