ARTHUR III  . (1393–1458), earl of Richmond, constable of France, and afterwards duke of Brittany, was the third son of John IV., duke of Brittany, and Joan of Navarre, afterwards the wife of Henry IV. of England . His brother, John V., gave him his earldom of Richmond in England . While still very young, he took part in the civil wars which desolated France during the reign of Charles VI . From 1410 to 1414 he served on the side of the Armagnacs, and afterwards entered the service of Louis the dauphin, whose intimate friend he became . He profited by his position at court to obtain the lieutenancy of the Bastille, the governorship of the duchy of Nemours, and the confiscated territories of Jean Larcheveque, seigneur of Parthenay . His efforts to reduce the latter were, however, interrupted by the necessity of marching against the English . At Agincourt he was wounded and captured, and remained a prisoner in England from 1415 to 1420 . Released on parole, he gained the favour of King Henry V. by persuading his brother, the duke of Brittany, to conclude the treaty of Troyes, by which France was handed over to the English king . He was rewarded with the countship of Ivry . In 1423 Arthur married Margaret of Burgundy, widow of the dauphin Louis, and became thus the brother-in-law of Philip the Good of Burgundy, and of the regent, the duke of Bedford . Offended, however, by Bedford's refusal to give him a high command, he severed his connexion with the English, and in March 1425 accepted the constable's sword from King Charles VII .

He now threw himself with ardour into the

French cause, and persuaded his brother, John V. of Brittany, to conclude with Charles VII. the treaty of Saumur (October 7, 1425) . But though he saw clearly enough the measures necessary for success, he lacked the means to carry them out . In the field he met with a whole series of reverses; and at court, where his rough and overbearing manners made him disliked, his influence was over-shadowed by that of a series of incompetent favourites . The peace concluded between the duke of Brittany and the English in September 1427 led to his expulsion from the court, where Georges de la Tremoille, whom he himself had recommended to the king, remained supreme for six years, during which Richmond tried in vain to overthrow him . In the meantime, in June 1429, he joined Joan of Arc at Orleans, and fought in several battles under her banner, till the influence of La Tremoille forced his withdrawal from the army . On the 5th of March 1432 Charles VII. concluded with him and with Brittany the treaty of Rennes; but it was not until June of the following year that La Tremoille was overthrown . Arthur now resumed the war against the English, and at the same time took vigorous measures against the plundering bands of soldiers and peasants known as routiers or ecorcheurs . On the loth of September 1435, mainly as a result of his diplomacy, was signed the treaty of Arras between Charles VII, and the duke of Burgundy, to which France owed her salvation . On the 13th of April 1436, Arthur took Paris from the English; but he was ill seconded by the king, and hampered by the necessity for leading frequent expeditions against the ecorcheurs; it was not till May 1444 that the armistice of Tours gave him leisure to carry out the reorganization of the army which he had long projected . He now created the compagnies d'ordonnance, and endeavoured to organize the militia of the francs archers . This reform had its effect in the struggles that followed . In alliance with his nephew, the duke of Brittany, he reconquered, during September and October 1449, nearly all the Cotentin; on the 15th of April 1450 he gained over the English the battle of Formigny; and during the year he recovered for France the whole of Normandy, which for the next six or seven years it was his task to defend from English attacks .

On the

death of his nephew Peter II., on the 22nd of September 1457, he became duke of Brittany, and though retaining his office of constable of France, he refused, like his predecessors, to do homage to the French king for his duchy . He reigned little more than a year, dying on the 26th of December 1458, and was succeeded by his nephew Francis II., son of his brother Richard, count of Etampes . Arthur was three times married: (1) to Margaret of Burgundy, duchess of Guienne (d . 1442); (2) to Jeanne d'Albret, daughter of Charles II. of Albret (d . 1444) ; (3) to Catherine of Luxemburg, daughter of Peter of Luxemburg, count of St Poi, who survived him . He left no legitimate children .