Although the earliest inscriptions at the site date to circa 550–500 BCE, archaeological excavations conducted for more than a century have recovered artifacts as early as the Mycenaean era, many now at the National Archaeological Museum of Athens, and some in the archaeological museum at nearby Ioannina. Archaeologists also have found Illyrian dedications and objects that were received by the oracle during the seventh century BCE. Until 650 BCE, Dodona was a religious and oracular centre mainly for northern tribes: only after 650 BCE did it become important for the southern tribes.
Originally Dodona was an oracle of the Mother Goddess attended by priestesses. She was identified at other sites as Rhea or Gaia. The oracle also was shared by Dione (whose name simply means "deity") and, by classical times, by Zeus (whose name also simply means "deity"). Many dedicatory inscriptions recovered from the site mention both "Dione" and "Zeus Naios". By classical times, elsewhere in Classical Greece Dione was relegated to a minor role, being made into an aspect of Zeus's more usual consort, Hera—but never at Dodona. After Dodona passed to the Molossians, according to Plutarch the worship of Zeus began there, being known as "Zeus Naios" or "Naos" (god of the spring below the oak in the temenos or sanctuary, cf. Naiads) and as "Zeus Bouleus" (Counsellor).
A deity also could be invoked from a distance. In Homer's Iliad (circa 750 BCE), Achilles prays to "High Zeus, Lord of Dodona, Pelasgian, living afar off, brooding over wintry Dodona". No buildings are mentioned, and the priests (called Selloi) slept on the ground with unwashed feet. The oracle also features in Odysseus's fictive yarn about himself, told to the swineherd Eumaeus: Odysseus, he tells Eumaeus, has been seen among the Thesprotians, having gone to inquire of the oracle at Dodona whether he should return to Ithaca openly or in secret (as the disguised Odysseus is doing). Odysseus later repeats the same tale to Penelope, who may not yet have seen through his disguise. His words "bespeak a familiarity with Dodona, a realization of its importance, and an understanding that it was normal to consult Zeus there on a problem of personal conduct."
Not until the fourth century BCE, was a small stone temple to Zeus added to the site. By the time Euripides mentioned Dodona (fragmentary play Melanippe), and Herodotus wrote about the oracle, the priestesses had been restored. Though it never eclipsed the Oracle of Apollo at Delphi, Dodona gained a reputation far beyond Greece. In Apollonius of Rhodes' Argonautica, a retelling of an older story of Jason and the Argonauts, Jason's ship, the "Argo", had the gift of prophecy, because it contained an oak timber spirited from Dodona.
In c. 290 BCE, King Pyrrhus made Dodona the religious capital of his domain and beautified it by implementing a series of construction projects (i.e. grandly rebuilt the Temple of Zeus, developed many other buildings, added a festival featuring athletic games, musical contests, and drama enacted in a theatre). A wall was built around the oracle itself and the holy tree, as well as temples to Dione and Heracles.
In 219 BCE, the Aetolians, under the leadership of General Dorimachus, invaded and burned the temple to the ground. During the late 200s BC, King Philip V of Macedon (along with the Epirotes) reconstructed all the buildings at Dodona.[20] In 167 BCE, Dodona was destroyed by the Romans (led by Aemilius Paulus), but was later rebuilt by Emperor Augustus in 31 BCE. By the time the traveller Pausanias visited Dodona in the second century CE, the sacred grove had been reduced to a single oak. In 241 CE, a priest named Poplius Memmius Leon organized the Naia festival of Dodona. In 362 CE, Emperor Julian consulted the oracle prior to his military campaigns against the Persians.
Pilgrims still consulted the oracle until 391-392 CE when Emperor Theodosius closed all pagan temples, banned all pagan religious activities, and cut down the ancient oak tree at the sanctuary of Zeus. Although the surviving town was insignificant, the long-hallowed pagan site must have retained significance for Christians given that a Bishop Theodorus of Dodona attended the First Council of Ephesus in 431 CE.
Source: wikipedia.org