There is an inverse correlation, in other words, between fame and ‘authenticity’ in the strictest sense. The Colosseum is a classic instance of this rule. A large proportion of what you see when you visit is much later than the original work of Vespasian and Titus in the 70s AD. The puzzle of dating the individual parts and the different phases has kept archaeologists amused for centuries. The truth is, though, that – despite the confident assertions of most guidebooks – it is now impossible in many cases to be certain which bits were built when. The usual euphemism that the ‘skeleton’ of the building is still essentially in its original form may be true enough, but it glosses over the question of how much of the building counts as the skeleton.The monument has suffered all kinds of damage – from fire, earthquake and other natural and man-made disasters – throughout its history. There are records of repairs up to perhaps as late as the early sixth century AD, commemorated in inscriptions that have been discovered in the building (the latest one documents the restoration of ‘the arena and the podium, which had collapsed in an abominable earthquake’).