René of Anjou (Renato; Rainièr; 16 January 1409 – 10 July 1480) was Duke of Anjou and Count of Provence from 1434 to 1480, who also reigned as King of Naples as René I from 1435 to 1442 (then deposed). Having spent his last years in Aix-en-Provence, he is known in France as the Good King René (Rei Rainièr lo Bòn; Le bon roi René).
René was a member of the House of Valois-Anjou, a cadet branch of the French royal house, and the great-grandson of John II of France. He was a prince of the blood, and for most of his adult life also the brother-in-law of the reigning king Charles VII of France. Other than the aforementioned titles, he was for several years also Duke of Bar and Duke of Lorraine.
René was born on 16 January 1409 in the castle of Angers. He was the second son of Duke Louis II of Anjou, King of Naples, by Yolanda of Aragon. René was the brother of Marie of Anjou, who married the future Charles VII and became Queen of France.
Louis II died in 1417 and his sons, together with their brother-in-law Charles, were brought up under the guardianship of their mother. The elder son, Louis III, succeeded to the crown of Sicily and the Duchy of Anjou; René then became Count of Guise. In 1419, when René was only ten, he was legally married to Isabella, elder daughter of Charles II, Duke of Lorraine.
René, then only ten, was to be brought up in Lorraine under the guardianship of Charles II and Louis, cardinal of Bar, both of whom were attached to the Burgundian party, but he retained the right to bear the arms of Anjou. He was far from sympathizing with the Burgundians. Joining the French army at Reims in 1429, he was present at the consecration of Charles VII. When Louis of Bar died in 1430, René inherited the duchy of Bar. The next year, on his father-in-law's death, he succeeded to the duchy of Lorraine. The inheritance was contested by the heir-male, Antoine de Vaudemont, who with Burgundian help defeated René at Bulgneville in July 1431.