queen of Naples whose long reign (1414–35) was marked by a succession of love affairs, by continual intrigues, and by power struggles over her domain between the French house of Anjou and that of Aragon, in Spain.

After her first husband, William of Austria, died in 1406, Joan is reported to have led a promiscuous life. When her brother Ladislas died in 1414, she became queen and appointed her lover Pandolfello Alopo grand chamberlain. Alopo temporarily removed from power the condottiere Muzio Attendolo Sforza (Sforza, Muzio Attendolo), an important figure in the previous regime. On July 14, 1415, Joan married Jacques de Bourbon, Count de la Marche, who, confident of his power, soon had Alopo executed (1415), usurped the queen's power, and demanded the death of a Neapolitan baron who led the opposition to the increasing French influence in Naples. The barons, who had arranged the marriage in the first place, rebelled, forcing Jacques to leave Naples.

Joan appointed her next lover, Giovanni Caracciolo (called Sergianni), as grand seneschal; he made peace with Sforza and appointed him grand constable. Nevertheless, Sforza supported Louis III of Anjou's claim to the Neapolitan throne. Joan thereupon called on Alfonso V the Magnanimous of Aragon for aid, adopting him as her heir. Alfonso arrived in Naples in July 1421 and began to intervene in Neapolitan affairs. When Joan and Caracciolo invited Sforza back to Naples, Alfonso arrested Caracciolo and besieged Joan in Castle Capuano (1423). After Sforza rescued her, she renounced her adoption of Alfonso and recognized Louis as heir. Alfonso was soon forced out of Naples.

The increasingly powerful Caracciolo tried to isolate the queen and made new overtures to Alfonso. He was assassinated, however, by plotting nobles (August 1432). Joan later disinherited Louis and readopted Alfonso (April 1433) and then readopted Louis in June. When Louis died (Nov. 14, 1434), she recognized as her heir his son René of Anjou, whom Alfonso drove from Naples a few years after Joan's death.