Lilaea appears for the first time in Homer's Iliad, listed among the nine Phocian towns that sent ships to Troy in the Catalogue of Ships — one of the earliest surviving inventories of Greek geography. The city took its name from the Naiad Lilaea, daughter of the river-god Cephissus, because the settlement stood at the very sources of that river. This was not incidental. In ancient Greek religious understanding, a city at the spring of a great river occupied a privileged position: it was the place where the divine flow began. Two sanctuaries stood here in antiquity, one dedicated to Artemis and another to the deified Cephissus himself — a god worshiped as a living presence in the water that gave the valley its life. The Naiad Lilaea was the personification of that spring, and the city bearing her name was, in a sense, built on a deity.

Ancient Lilaea's history is one of persistence under pressure. The region had been inhabited since the third millennium BCE; the polis itself became a city-state of some importance, well enough fortified that Herodotus does not list it among the Phocian cities destroyed by the Persians — either because it submitted to the district of Doris, which had already made terms with Xerxes, or, as numismatic and epigraphic evidence suggests more likely, because its walls were simply too strong to storm. Philip II of Macedon destroyed it in 346 BCE during the Third Sacred War, the same campaign that leveled Daulis. It was rebuilt. Philip V of Macedon later besieged it and installed a garrison; the city rose against the garrison under the leadership of a man named Patron, defeated the Macedonians, and negotiated a formal withdrawal. The fortification hill, still called 'Pyrgos' or 'Palaeokastro,' and the walls to the east of the modern village of Lilaia, are the physical residue of that long defensive career.

When the Greek traveler Pausanias visited Lilaea in the second century CE, he found a functioning city: a theatre, an agora, public baths, a temple of Apollo and a temple of Artemis. The statues inside those temples were of Athenian workmanship and carved from Pentelic marble — the same luminous white stone used for the Parthenon. This is a detail worth pausing on. Pentelic marble was quarried near Athens, roughly 150 kilometers away, and commissioning Athenian sculptors to fill a provincial Phocian temple was a statement of civic ambition and cultural aspiration. By Pausanias's day Lilaea was beginning to decline, but it had not yet lost the will to present itself as a place of consequence. The architectural members by the springs of Agia Eleoussa — where the fountain and temple of Cephissus stood — are still visible today, as are Byzantine remains: a basilica dedicated to St. Christopher, and a church from the 10th or 11th century dedicated to St. Eleoussa.

The ritual of throwing sweets into the Cephissus at Lilaea, trusting they would emerge at Castalia, is one of the more affecting images from ancient Phocian religious life. It implies a theology of connection: that this city, tucked against the northern flank of Parnassus, was not peripheral to the world's center but was, in fact, its headwater. Whatever Delphi gave — prophecy, orientation, sacred water — began here, in the spring the goddess Lilaea animated. The Frankish period added its own layer to the site, reinforcing the walls with a new circuit. The modern village of Lilaia, whose name preserves the ancient one almost unchanged, stands near the ancient ruins. In late spring, when the Cephissus runs full with snowmelt from the heights of Parnassus above, it is not difficult to understand why a city built here believed the whole sacred landscape downstream was, in some sense, its own.