A major fire broke out in the Parthenon shortly after the middle of the third century AD which destroyed the Parthenon's roof and much of the sanctuary's interior. Repairs were made in the fourth century AD, possibly during the reign of Julian the Apostate. A new wooden roof overlaid with clay tiles was installed to cover the sanctuary. It sloped at a greater incline than the original roof and left the building's wings exposed.
The Parthenon survived as a temple dedicated to Athena for close to a thousand years until Theodosius II decreed in 435 AD that all pagan temples in the Byzantine Empire be closed. At some point in the fifth century, Athena's great cult image was looted by one of the emperors and taken to Constantinople, where it was later destroyed, possibly during the siege of Constantinople during the Fourth Crusade in 1204 AD.