Many roads lead to Byzantium, ‘the New Rome’, and guidance comes from dozens of disciplines, including art history and archaeology, theology and expertise in stone inscriptions, coins or handwriting. Indeed, those general historians who act as guides have themselves often majored in other fields, such as ancient Greece and Rome, the medieval west, the Slav or Mediterranean worlds, and even the Italian renaissance. The surest fact about the elusive ‘New Rome’ is that it lasted over a thousand years, albeit with a fifty-seven-year dislocation from 1204. Across this millennium, the questions of how, why and where the empire survived, receded and (most importantly) revived as a more or less functioning organism – and as an idea – underlie this book.