Noun
(historical fiction) One of the legendary "twelve peers" or renowned warriors of Charlemagne, the Emperor of the Romans from 800 to 814. [13th–17th c.; revived 19th c.]
(by extension, historical) One of the twelve nobles granted feudal territories or episcopal sees by the King of France in return for their fealty (namely the Archbishop-Duke of Rheims; the Bishop-Dukes of Laon and Langres; the Bishop-Counts of Beauvais, Chalons, and Noyon, the Dukes of Normandy, Burgundy, and Aquitaine; and the Counts of Toulouse, Flanders and Champagne). [13th–17th c.; revived 19th c.]
Synonym: paladin
(by extension) An individual considered to be like or in the model of Charlemagne's peers; someone considered a great hero or paladin. [14th–16th c.; revived 19th c.]
Source: en.wiktionary.org