Larymna's story is a small lesson in how fluid ancient borders could be. Upper Larymna began as a Locrian town, listed by the poet Lycophron among the holdings of Ajax the Lesser, and Pausanias says it later joined the Boeotian League of its own accord as Theban power grew — most likely after Cassander rebuilt Thebes, since an earlier coastal survey still files it under Locris. By 230 BC it counts as Boeotian; in the time of the Roman general Sulla, Boeotian still. When the Romans finally merged Upper Larymna into the Lower town, the upper settlement's people were resettled below and the old town simply emptied out and was abandoned.

Lower Larymna's fortune was geography. Landlocked Boeotia — home to Lebadeia, Chaeroneia, Orchomenus, Copae and a string of inland towns — needed a window onto the eastern sea, and Larymna's port became the most convenient one. As trade flowed through, the harbor town swelled in importance, outgrowing its upper namesake until it was plainly the greater of the two. That is why Pausanias, visiting later, mentions only one Larymna: the lower city was the one that still counted, and he never records the river's underground emergence because he likely never climbed to the upper site where it happened.

The English antiquary William Martin Leake came through in the mid-nineteenth century and left a careful record of what remained. The circuit of the walls measured less than a mile, and in places they still stood nearly half their original height — built of a soft red stone, badly eaten by the salt air, and patched in stretches with rough, unworked masses of rock. A tall stone tomb, the sorus, stood where it had always stood, perched on the rocks, its inscription and carved ornament by then worn smooth and unreadable. The ruins spread over a brush-covered flat ten minutes' walk from the river mouth, on the shore of a bay where the water runs strikingly deep.

Two small details give Lower Larymna its texture. Near the ruins lies the Glyfonero, a deep little pool of brackish, salt-laced water that the people of Leake's day swore had a cleansing, cathartic power. And the deep bay itself solved an old textual puzzle: where one passage of Pausanias seemed to mention a lake at Larymna, scholars argued the word should instead read "a harbor very deep," since no land-locked lake exists here at all — only the steep blue water of the sea. It is a fitting last word for a town that lived and died by its harbor, where a river that hid itself underground finally ran out into the open Aegean light.