The East Building was, above all, an entrance. Built in the mid-second century BC at the south end of the Agora, it formed the eastern wall and main gateway of an enclosed courtyard called the South Square. The cleverness was in its slope. Outside, along the Panathenaic Way climbing toward the Acropolis, the ground sat high. Inside the courtyard, it lay nearly two meters lower. So the building swallowed the difference: visitors descended a staircase from the avenue onto a terrace, crossed a long hall, then dropped down a second internal staircase to emerge in the square below. It was a piece of architectural choreography, a controlled passage from the public street into a guarded enclosure.

What was that enclosure for? Scholars have argued for a century, proposing a gymnasium, a marketplace, or a law court. The court theory is the most evocative. On this reading, the twelve marble blocks held wooden chests, one for each of the twelve tribes into which the Athenian people were divided. Jurors arriving for duty placed their bronze name-tickets, called pinakia, into their tribe's chest. The tickets were then fed into stone allotment machines, the kleroteria, which randomly assigned citizens to courts. No one could buy or bribe a seat, because no one knew in advance where he would sit. Aristotle described this dazzling anti-corruption system in detail. The East Building may be where it physically began each morning, jurors waiting on the terrace for the lottery to seat them.

Athens was a battered city by the late Republic. In 86 BC the Roman general Sulla stormed and sacked it, and the East Building likely fell then. What came next is a vivid lesson in how the ancient world recycled itself. Iron smelters set up in the ruins. Then marble workers moved in, using those same twelve bedding blocks as workbenches to saw slabs of stone; the saw marks are still visible, and the white sludge from the cutting settled in a layer three-quarters of a meter thick in the wreckage next door. The building was patched back up in the second century AD, then damaged again when the Heruli sacked Athens in 267. Its stones were finally hauled off to build the hasty defensive wall thrown up after that disaster.

For sixteen centuries it lay buried. In 1952 the archaeologist Margaret Crosby, digging for the American School of Classical Studies, uncovered the first traces. The team's first instinct was to call it the East Stoa, picturing a colonnaded porch. Closer study killed that idea: the foundations were too weak to carry columns, so the name was quietly changed to the plainer East Building. It is an unglamorous structure, a vestibule rather than a temple, with no soaring marble to photograph. Yet that is its appeal. The famous monuments of Athens show us how the city worshipped and remembered. A building like this, all staircases and sorting and locked entrances, shows us how it actually governed itself, one carefully controlled doorway at a time.