The
sanctuary, in any case, flourished from the second millennium BC until the 4th century BC. The site was destroyed
by barbarians during the 6th century AD. The site was rediscovered in 1873 by Konstantin Karaponos, who found some bronze
objects there (now housed in the museum in Athens).
Since 1952 the Greek Archaeological Service has carried out excavations and some restorations have been made. The seating of the 3rd century BD Stadium rises on the north side on a bank through up against the retaining wall on the west of the Theater, which restored in 1960-63 for the annual drama festival.
The 19th century reconstruction of the Theater was done quite well and very carefully, from what had been little more
than a heap of stones. It was built around 297-272 BC and destroyed by the Aetolians in 219BC ; it was rebuilt by Philip V
of Macedon with the his spoils taken from Thermon. The Romans damaged it during the 2nd century BC and it was converted
into an arena (for gladiatorial and animal combats) around the time of Augustus. The outer fascade of the stage(skene) had a
stoa with 13 octagonal columns, and an Arch that opened to the stage's center. Double Gateways with Ionic half-columns lead
into either parodos; the orchestra has a horseshoe shaped drainage channel. The Cavea is partly recessed in the side of the
Acropolis hill and partly supported by massive retaining walls of rusticated ashlar masonry up to 12 meters high, buttressed
by towers. A Ceremonial Entrance from the direction of the Acropolis opens into the topmost gallery, and there are cuttings
that show where a gate was fitted. The theater was one of the largest on the mainland, rivaled only by those at Argos and
Megalopolis. Its setting is quite wonderful, facing out on a green valley to the slopes of Mt. Tomaros.
The Acropolis had a surrounding wall with foundations four or five meters wide, and towers on three sides. The area is largely overgrown. A path descends to the terrace east of the Theater, which is the site of the Sanctuary, of which only foundations remain. There was no actual temple until the end of the 5th century BC; until then the sacred oak was the focus of worship. It stood alone within a circle of votive tripods and cauldrons. By the time of Pyrrus Ionic colonnades had been added, this structure sacked in 219 BC by the Aetolians and a larger temple was built with a propylaion which survived until the 4th century AD, when the oak tree was cut down by Christian zealots. An oak tree was planted there in recent times by an archaeologist with respect for the ancient mysteries.
Nearby are ruins of an early Christian basilika built on top of a sanctuary of Iraklis (Hercules), with with stumps of columns visible. During excavations in 1952, many oracular inscriptions were found scattered around the site, which are displayed in the archaeological museum in Ioannina. The site is open daily 8am-5pm; admission 2 euros. It is far less visited than Delphi, which eclipsed it long ago, and both the site and village are very unspoilt. There are good places to camp,as well as some rooms and local tavernas in the village.