The Doric Tetrapolis — the four-city league of Doris — consisted of Erineus, Boium, Cytinium, and Pindus (also called Akyphas). Erineus was the most important, sometimes called Dorium. Herodotus, writing in the fifth century BC, placed the district between Malis and Phocis, which matches the valley of the Apostolia river, a tributary of the Cephissus, perfectly. The valley's opening faces south toward Phocis but sits higher than the Cephissus lowlands, giving it a cool, enclosed character that the ancient geographers consistently noted. Strabo, describing the region centuries later, found Dorian settlements spread along Mount Oeta beyond the valley itself — the Dorians, it seemed, had never been strictly confined within these narrow limits. A mountain pass led across Parnassus from Doris to Amphissa in Ozolian Locris; at its head stood Cytinium, which suggests the district had genuine strategic value despite its small size.

Doris, the tradition held, was not always called Doris. Before the Dorians arrived, the valley was called Dryopis, named for its earlier inhabitants the Dryopes. According to the mythological accounts, Heracles and the Malians expelled the Dryopes from the valley, making room for the people who would eventually give the district their name. Whether this reflects any historical memory or is simply origin-story layering is impossible to say. Herodotus recorded a migration narrative of his own: the Dorians had previously lived in Phthiotis, then at the foot of Ossa and Olympus, then on Mount Pindus, then in Dryopis, before finally arriving in Doris. Each migration is attributed to expulsion by someone else — the Cadmeans, then circumstances that are left vague. Herodotus himself was careful to note that his account rested on tradition rather than historical evidence.

The Lacedaemonians took their responsibility to their metropolis seriously. On more than one occasion, Sparta sent military assistance to Doris when the Phocians or other neighbors threatened. Thucydides notes that Doris was a flashpoint for tension between Sparta and Phocis a full generation before the Peloponnesian War. During the invasion of Xerxes, the towns of Doris submitted to the Persians — and, as a result, were spared the destruction that Phocian towns suffered. In the third century BC, the Doric Tetrapolis joined the Aetolian League, a pragmatic alliance that reflected the valley's need for protection. The wars of the Phocians, Aetolians, and Macedonians took their toll. By the time Strabo wrote in the Roman period, he marveled that any trace of the old towns remained at all.

Today the modern municipality of Dorida covers roughly the same geographic area as the ancient district. The name survived everything — the Phocian wars, the Macedonian conquest, the Roman absorption, the Byzantine centuries, the Ottoman occupation — and it still sits on maps of central Greece, just south of Mount Oeta, between the same mountains that Herodotus described. The valley of the Apostolia river is quiet now, without the political weight it once carried. But the word Dorian still appears in every history of ancient Greece, every account of architecture, dialect, and colonization that spread Doric culture across the Mediterranean. All of it traces back, at least in the ancient telling, to this small mountain valley that a passing traveler could cross in an afternoon.