The terms Byzantine Empire (a historiographical term use since the 19th century) and Eastern Roman Empire are expressions used to describe the Roman Empire of the Middle Ages, centered on its capital of Constantinople, referred to by its inhabitants simply as the Roman Empire (in Greek Βασιλεία Ῥωμαίων) or Romania (Ῥωμανία), its emperors continuing the unbroken succession of Roman emperors, preserving Greco-Roman legal and cultural traditions; to the Islamic world it was known primarily as روم (Rûm, "land of the Romans"). Due to the dominance of Medieval Greek language, culture and population, it was known to many of its western European contemporaries as Empire of the Greeks.