When in Western Europe the remnants of the Roman Empire were nothing more than small weak states, Constantinople remained the capital of a powerful organized state. It was a state with administrative structures, legislation that was modernized and adapted to its needs, a currency that circulated throughout the world, from the Mediterranean to the Far East, an educational system that preserved the cultivation of the Greek language and education. It was an empire that relied on a hierarchical society, which bequeathed to the later generations, apart from its own perception of Christianity, some of the masterpieces of world art. The existence of present-day Europe owes to this empire: If the Byzantine Empire had not restrained the Arabs, the Seljuks, and the Ottomans for so many centuries, the West would not have had time to stand up. These are some of the answers that Judith Herrin gives to the question "What is Byzantium". The Byzantinologist author of the widely read "Women in Purple" ("Oceanida" 2002) guides the reader through all aspects of this phantasmagoric but also full of surprises empire that dominated the stage of History for over a thousand years.