Pandion was no ordinary honoree. When the Athenian democracy reorganized itself into ten tribes, each was assigned a legendary patron - an eponymous hero whose name the tribe carried. Pandion gave his name to the tribe Pandionis, and his shrine was that tribe's spiritual headquarters, most likely named for one of the two early kings of Athens who bore the name. This was a heroon, a hero-shrine, where citizens connected their everyday political identity to the deep myth of their city's founding. The second-century traveler Pausanias climbed the Acropolis and recorded seeing a statue of Pandion standing here, on the rock's eastern side.

The Perserschutt - the "Persian rubble" - is one of archaeology's strange gifts. After Xerxes' army sacked Athens and shattered the Acropolis sculptures, the returning Athenians treated the broken offerings as sacred. Rather than discard them, they buried the fragments, sealing a single catastrophic moment beneath the platforms of the rebuilt sanctuary. The Calf-Bearer and the Athena head emerged from exactly this layer in the foundations here, which is how the building can be dated and tied to the great rebuilding of the fifth century. The shrine, in other words, literally stands on the memory of the city's destruction.

The structure itself is modest. Archaeologists call it Building IV, a roofless rectangle open to the sky, divided into two nearly equal halves by an interior wall and entered through a projecting porch on its west-northwest side. It went up in the late fifth century BC, replacing an earlier structure that was torn down to make room - on ground levelled when the Acropolis circuit wall was built. That timing places it within the sweeping construction program of Pericles, the same era that gave Athens the Parthenon. In 1946 the American archaeologist Gorham Stevens proposed that the northern room became the Pandion shrine while the southern half served as a workshop for storing tools and stone.

Nothing here is settled. The identification rests on inference rather than a found inscription naming Pandion on the spot, and not every scholar accepts it. Noel Robertson argued that the real Sanctuary of Pandion lay further northwest, near the Sanctuary of Zeus Polieus, and that Building IV instead belonged to Erechtheus, another mythic king. So the visitor stands before stones that may honor one legendary founder or another - a fitting puzzle for a place built to anchor Athenian identity in a past too old to verify. Hadrian may even have made this shrine the seat of his Panhellenion, the league of Greek cities he founded in the 130s AD, binding the new Roman order to the oldest Athenian myth.