The most important temple in ancient Amvrakia was sacred to Apollo Pythios Sotir. Then dominating the city of Amvrakia, the temple now stands at the centre of the city of Arta, near the Kilkis Square. On the base of poros stone architectural members that were found interspersed in the surroundings, it is dated to about 500 BC; however, earlier sanctuaries dedicated to Apollo must have been erected at the same location. As it seems, this temple being the main sanctuary of the city, the authorities entrusted public documents and texts, to conclude from the finding of an important public document, an inscribed stele (standing block) which featured the text of a treaty defining the limits between the two cities of Amvrakia and of Haradros; the stele is dated to the second century BC, immediately after the Roman conquest of the city, and is a valuable source of information as to the administration of continental cities.
The majestic peristyle temple was built according to the Doric rhythm, and disposed of a pronaos (anteroom) and a longitudinal cella building (in Greek sek?s), of dimensions 44 x 20.75m. At the far end of the cella survives the foundation of the pedestal supporting the statue or the symbol of the god Apollo. Only the crepis (stone base) and the euthynteria (levelling course just above the walking surface) are preserved of the monument, since already from the early Christian times its stone material was gradually removed and the monument was used as a quarry; during the same period, tombs with tiled roofs were constructed among the ancient ruins.
In 1964 the existence of the monument became a fact, initiating a test investigation by the archeologist Mrs. Ioulia Vokotopoulou. The excavation went on during 1966 and 1968 and finished between 1975 and 1977.