The Roman Empire (Βασιλεία Ῥωμαίων) or Romania (Ῥωμανία), more commonly known as the Byzantine Empire, Byzantium or simply Greece is a sovereign constitutional monarchy located in the eastern Mediterranean, in both Europe and Asia.
It comprises of mainland Greece, numerous islands in the Aegean and elsewhere (Crete, Cyprus, Rhodes, Lesbos etc.), the western part of Asia Minor and Trebizond. The highest point is Mt. Olympus.
Byzantium is a democratic, highly developed country with an advanced economy. It is one of the major regional powers in the Mediterranean. It is a member of the UN, EU (but it didn't adopt the euro, similarly to the UK, Denmark or Sweden), NATO, Council of Europe, OECD, WTO and other international organizations.