Arthur III ( br, Arzhur), more commonly known as Arthur de Richemont (24 August 139326 December 1458), was briefly
Duke of Brittany
This is a list of rulers of the Duchy of Brittany. In different epochs the sovereigns of Brittany were kings, princes, and dukes. The Breton ruler was sometimes elected, sometimes attained the position by conquest or intrigue, or by hereditary r ...
from 1457 until his death. He is noted primarily, however, for his role as a leading military commander during the
Hundred Years' War
The Hundred Years' War (; 1337–1453) was a series of armed conflicts between the kingdoms of England and France during the Late Middle Ages. It originated from disputed claims to the French throne between the English House of Plantag ...
. Although Richemont briefly sided with the English once, he otherwise remained firmly committed to the
House of Valois
The Capetian house of Valois ( , also , ) was a cadet branch of the Capetian dynasty. They succeeded the House of Capet (or "Direct Capetians") to the French throne, and were the royal house of France from 1328 to 1589. Junior members of the ...
. He fought alongside
Joan of Arc
Joan of Arc (french: link=yes, Jeanne d'Arc, translit= �an daʁk} ; 1412 – 30 May 1431) is a patron saint of France, honored as a defender of the French nation for her role in the siege of Orléans and her insistence on the corona ...
, and was appointed
Constable of France
The Constable of France (french: Connétable de France, from Latin for 'count of the stables') was lieutenant to the King of France, the first of the original five Great Officers of the Crown (along with seneschal, chamberlain, butler, and ch ...
. His military and administrative reforms in the French state were an important factor in assuring the final defeat of the English in the Hundred Years' War.
The name Richemont reflects the fact that he inherited the English title of
Earl of Richmond
The now-extinct title of Earl of Richmond was created many times in the Peerage of England. The earldom of Richmond was initially held by various Breton nobles; sometimes the holder was the Breton duke himself, including one member of the ...
, which was held by previous dukes of Brittany, but his tenure was never recognized by the English crown. At the very end of his life he became