Basileus (Greek: βασιλεύς)[n 1] is a Greek term and title that has signified various types of monarchs in history. In the English-speaking world it is perhaps most widely understood to mean "king" or "emperor". The title was used by sovereigns and other persons of authority in ancient Greece, the Byzantine emperors, and the kings of modern Greece.
The feminine forms are basileia (βασίλεια), basilis (βασιλίς), basilissa (βασίλισσα), or the archaic basilinna (βασιλίννα), meaning "queen" or "empress".[1]
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