Duke

duke

European title of nobility, the highest rank below a prince or king except in countries having such titles as archduke or grand duke. The wife of a duke is a duchess. The Romans gave the title dux to high military commanders with territorial responsibilities. It was adopted by the barbarian invaders of the Roman Empire and was used in their kingdoms and also in France and Germany for rulers of very large areas. In some European countries a duke is a sovereign prince who rules an independent duchy. In Britain, where there were no ducal titles until 1337, it is a hereditary title.

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Duke 

among ancient Germanic peoples, a duke (Herzog) was the elected military leader of a tribe (Latin dux). In Western Europe during the early medieval period, duke meant a tribal prince; during the period of feudal fragmentation, the title signified a major landholder (in the hierarchy of military vassalage, the duke occupied the second most important place after the king). After feudal fragmentation was overcome, duke was one of the highest titles of nobility.