Joanna I, also known as Johanna I (; December 1325 – 27 July 1382), was Queen of Naples, and Countess of Provence and Forcalquier from 1343 to 1382; she was also Princess of Achaea from 1373 to 1381.
Joanna was the eldest daughter of Charles, Duke of Calabria and Marie of Valois to survive infancy. Her father was the son of Robert the Wise, King of Naples, but he died before his father in 1328. Three years later, King Robert appointed Joanna as his heir and ordered his vassals to swear fealty to her. To strengthen Joanna's position, he concluded an agreement with his nephew, King Charles I of Hungary, about the marriage of Charles's younger son, Andrew, and Joanna. Charles I also wanted to secure his uncle's inheritance to Andrew, but King Robert named Joanna as his sole heir on his deathbed in 1343. He also appointed a regency council to govern his realms until Joanna's 21st birthday, but the regents could not actually take control of state administration after the King's death.
Joanna's personal life crucially affected the political stability of the Kingdom of Naples (murder of her first husband Andrew in 1345, the invasions of King Louis I of Hungary—justified as avenging the death of his brother—and her three later marriages with Louis of Taranto, James IV, titular King of Majorca and Otto, Duke of Brunswick-Grubenhagen) and undermined her position with the Holy See; moreover afterwards, during the Western Schism, she chose to support the Avignon Papacy against Pope Urban VI, who in retaliation declared her a heretic and usurper on 11 May 1380.
With all her children having predeceased her, Joanna's heirs were the descendants of her only surviving sister Maria, whose first marriage with their cousin Charles, Duke of Durazzo was performed without her permission, becoming both spouses in the heads of the political faction against Joanna. Trying to reconcile with the Durazzo branch and with the purpose to secure her succession, Joanna arranged the marriage of her niece Margaret of Durazzo with her first cousin (and Joanna's second cousin) Charles of Durazzo, who eventually captured and imprisoned Joanna, and finally ordered her assassination on 27 July 1382.
Early years
Joanna was the eldest surviving child of Charles, Duke of Calabria (only surviving son of Robert the Wise, King of Naples), and Marie of Valois (sister of King Philip VI of France). The Renaissance historian Donato Acciaioli claimed that she had been born in Florence, but she may have actually been born during her parents' travel towards the town, according to scholar Nancy Goldstone. The precise date of Joanna's birth is unknown; according to some researchers, she was most probably born in 1326 or 1327; however, given the fact that her mother gave birth to four or five children during her four years' marriage, Joanna was probably born in either December 1325 or early 1328. The early deaths of two of her siblings —A daughter, variously named Eloisa, Louise or Maria (born in January/February 1325; died 27 December 1325) and Charles Martel (born 13 April 1327; died eight days later)— left Joanna as the second in line to the Neapolitan throne after her own father.
Charles of Calabria died unexpectedly on 9 November 1328. With his death, his father faced the problem of succession, because Charles' posthumous child was also a daughter, Maria, born on 6 May 1329. Although Neapolitan law did not prevent women from inheriting the throne, the concept of a reigning queen was unusual. The agreement between the Holy See and Robert the Wise's grandfather, Charles I of Anjou, had explicitly acknowledged the right of Charles I's female descendants to inherit the throne, but it also stipulated that a female monarch was to marry and to allow her husband to rule. Furthermore, the Neapolitan royal house was a branch of the Capet dynasty of France and the French had recently excluded women from royal succession. Robert's nephew, Charles I of Hungary, had been disinherited in Robert's favor in 1296, but he did not abandon his claim to the Regno (or the Kingdom of Naples). Pope John XXII had ignored Charles's demands for years, but Robert's support for the Spiritual Franciscans (whom the Pope regarded as heretics) and his negligence to pay the yearly tribute to the Holy See gave rise to tensions between Naples and the Papacy. Robert's two younger brothers, Philip I, Prince of Taranto, and John, Duke of Durazzo, could also claim the throne against a female monarch.