Thomas De Quincey 
The Caesars 

The condition of the Roman Emperors has never yet been fully appreciated; nor has it been sufficiently perceived in what respects it was absolutely unique. There was but one Rome: no other city, as we are satisfied by the collation of many facts, either of ancient or modern times, has ever rivalled this astonishing metropolis in the grandeur of magnitude; and not many – if we except the cities of Greece, none at all – in the grandeur of architectural display…