Byzantine Empire

Imperial Emblem
Source:Wikipedia

The Byzantine Empire (Greek: Βασιλεία των Ρωμαίων) is the term conventionally used since the 19th century to describe the Greek-speaking Roman Empire of the Middle Ages, centered around its capital of Constantinople. In certain specific contexts, usually referring to the time before the fall of the Western Roman Empire, it is also often referred to as the Eastern Roman Empire. To its inhabitants, the Empire was simply the Roman Empire and its emperors continued the unbroken succession of Roman emperors.