King

A king (rex in Latin) is a sovereign who rules over an area usually referred to as a kingdom. While the term queen applies to female sovereigns, the term king usually refers specifically to male sovereigns, though the term has occasionally been applied to females in a way that implies a specific status without reference to gender.

Leaders of various titles and statuses had existed in Europe prior to the Middle Ages, including warlords, chieftains and emperors, but the development of kingdoms with relatively stable borders, ruled over by sovereign kings, was one of the defining developments of medieval society. In many areas of Iron Age Europe (and persisting into the Middle Ages in Norway and Italy), the land was divided into smaller petty kingdoms, where petty kings (usually a warlord or clan leader) ruled. The petty kingdoms of Norway were famously conquered by Harald Fairhair (who, according to the saga Heimskringla, was called "Harald Tanglehair" until his conquest, as he had vowed never to comb his hair until he ruled all of Norway) in the 9th century.

Etymology
The word king comes from Old English (Anglo-Saxon) cyning, a cognate of Old English cyn, meaning "family" or "kin". The relationship of king to cognate kin may be an indication of the hereditary nature of kingship. Non-English cognates indicating a male sovereign include: Danish konge, Dutch koning, Finnish kuningas, German könig, Norwegian konge, and Swedish kung.