The Parthenon was never only a temple. Built in the fifth century BC for Athena, it was converted into a Christian church dedicated to the Virgin Mary in late antiquity - the Church of Our Lady of Athens. When the Ottomans took the Acropolis, that church in turn became a mosque. The exact moment is undocumented, but Sultan Mehmed II, who had taken Constantinople in 1453, visited Athens in 1458 and again in 1460, and the conversion likely came around then, as prominent churches of conquered cities typically did. The structural changes were modest. A medieval Frankish tower at the southwest corner, perhaps once a bell tower, was adapted into a minaret. The Christian altar and screens were removed. Remarkably, a mosaic of the Virgin in the apse appears to have survived the conversion, an image of Mary left in place inside a working mosque.

On a September night in 1687, a Venetian army besieging the Acropolis turned its mortars on the citadel. The Ottoman defenders had stored gunpowder inside the Parthenon, treating the ancient temple as a magazine. A Venetian mortar round found it. The explosion blew out the centre of the building that had stood largely intact for more than two thousand years, hurling columns and sculpture across the rock and killing the people sheltering within. In a single blast, the Parthenon went from a roofed mosque to the roofless ruin we know today. The damage that defines the monument's silhouette - the gaping middle, the scattered marble - was not the slow work of time but the sudden violence of one wartime night.

The story did not end in the rubble. In the early eighteenth century, a second mosque was raised inside the shattered shell - a small, single-domed building standing in the cleared open space of the naos, the temple's inner chamber, now open to the sky. For more than a century this modest dome sat at the heart of the ancient ruin, an Ottoman place of prayer cradled within the broken classical walls. It was finally taken down in 1843, when archaeologists began the systematic excavation and restoration of the Acropolis - a project that aimed to recover the temple of antiquity and, in doing so, erased the more recent layers of the building's life.

Because both mosques were dismantled and the marble scrubbed of its Ottoman centuries, the evidence is thin. We know the place largely through travellers. The Ottoman writer Evliya Celebi, who visited in 1667, left the richest account in his Seyahatname, describing the building and weaving it into Islamic legend and folklore. European visitors followed - Jacob Spon, George Wheler, and the artist Jacques Carrey, whose drawings preserve sculptures since lost. Among the very last records is a daguerreotype taken in 1839 by Pierre-Gustave Joly de Lotbiniere, one of the earliest photographs of the Acropolis, which still shows the little mosque sitting quietly inside the Parthenon. Four years later it was gone, and the temple was returned, in memory and in stone, to the goddess Athena alone.