The Homeric Hymn to Apollo describes Crissa's founding in terms that made the city's sanctity inseparable from the god himself. A colony of Cretans, the hymn says, was led to the site by Apollo, who chose them to be his priests at the sanctuary he intended to establish at Pytho. The hymn locates Crissa under Parnassus, 'where no chariots rolled, and no trampling of horses was heard' — language that matches the rocky hilltop terrain, unsuited to wheeled traffic, on which the ruins would later be found. At this early stage in the ancient sources, Crissa and the oracle are almost indistinguishable. The sanctuary of Pytho lay within Crissa's territory; it had not yet become a separate town. Crissa held the rich plain stretching down to the sea, controlled access to Apollo's house, and gave its name to the entire gulf below — what older sources called the Crissaean Gulf, and which the wider world eventually came to call the Corinthian Gulf.

Crissa's dominance eroded from two directions at once. Down on the coast, its own port town of Cirrha — created to handle seaborne trade and the flow of pilgrims — grew in wealth and influence until it overshadowed its inland parent. Up in the mountains, the sanctuary of Pytho developed into the independent city of Delphi, which stopped deferring to Crissa's authority. By the time the First Sacred War erupted around 595 BCE, the sources no longer worry much about Crissa; it is Cirrha against which the Amphictyonic League directs its anger. The fate of Crissa in the aftermath is uncertain. It had most likely already declined well before the war, its population drifted away to Delphi and Cirrha. The city that once lent its name to the gulf had become a village on a hillside.

What survives at the site today are walls — very old, polygonal walls of the kind that specialists date to the early centuries of the first millennium BCE. By the mid-nineteenth century, when scholars first surveyed the site systematically, those walls still reached ten feet in height in places, and as broad as eighteen feet on the northern face and twelve on the western. They surround the church of the Forty Saints in the modern village of Chrisso — a name that carries the ancient sound directly into the present. Chrisso sits on the projecting spur of Parnassus that Pindar described: the hill over which the road from the Hippodrome on the coast climbed on its way up to Delphi. Standing among the church's old olive trees, with Parnassus rising steeply behind and the Crissaean plain falling away below toward the olive groves and the distant glint of the gulf, the position of the ancient city is immediately legible. It was a place built to watch and command.

Crissa left a disproportionately large mark on the historical record for a city that was already fading in antiquity. Its name appears in the Iliad, in the Homeric Hymns, in Pindar, in Nonnus. It gave the gulf its oldest name. It supposedly sent colonists who founded Metapontium in Magna Graecia, in what is now southern Italy — carrying the Crissaean identity across the Ionian Sea. The ancient writers were aware of the confusion between Crissa and its coastal successor Cirrha; Pausanias, the second-century CE traveller, mistakenly supposed the two were the same place under different names. They were not. Crissa was the older city, inland, rocky, tied to the earliest mythology of the oracle. Cirrha was the port that rose in its shadow and eventually eclipsed it. Both are gone, but the names persist — in Chrisso, in Kirra — still attached to the same ground.