Mediterranean, ending antiquity (see Pirenne Thesis). The original Roman Senate continued to express decrees into the late 6th century, and the last Eastern Roman emperor to use Latin as the language of his court in Constantinople was emperor Maurice, who reigned until 602. The overthrow of Maurice by his mutinying Danube army under Phocas resulted in the Slavic invasion of the Balkans and the decline of Balkan and Greek urban culture (leading to the flight of Balkan Latin speakers to the mountains, see Origin of the Romanians), and also provoked the Byzantine–Sasanian War of 602–628 in which all the great eastern cities except Constantinople were lost. The resulting turmoil did not end until the Muslim conquests of the 7th century finalized the irreversible loss of all the largest Eastern Roman imperial cities besides the capital itself. The emperor Heraclius in Constantinople, who emerged during this period, conducted his court in Greek, not Latin, though Greek had always been an administrative language of the eastern Roman regions. Eastern-Western links weakened with the ending of the Byzantine Papacy. The Eastern Roman empire's capital city of Constantinople was left as the only unconquered large urban center of the original Roman empire, as well as being the largest city in Europe. Yet many classical books, sculptures, and technologies survived there along with classical Roman cuisine and scholarly traditions, well into the Middle Ages, when much of it was "rediscovered" by visiting Western crusaders. Indeed, the inhabitants of Constantinople continued to refer to themselves as Romans, as did their eventual conquerors in 1453, the Ottomans. (see Rûm and Romaioi.) The classical scholarship and culture that was still preserved in Constantinople were brought by refugees fleeing its conquest in 1453 and helped to spark the Renaissance (see Greek scholars in the Renaissance). Ultimately, it was a slow, complex, and graduated change in the socio-economic structure in European history that led to the changeover between classical antiquity and medieval society and no specific date can truly exemplify that. Political revivalism In politics, the late Roman conception of the Empire as a universal state, headed by one supreme divinely appointed ruler, united with Christianity as a universal religion likewise headed by a supreme patriarch, proved very influential, even after the disappearance of imperial authority in the west. This tendency reached its peak when Charlemagne was crowned "Roman Emperor" in the year 800, an act which led to the