First attempt (1449) In 1421 the childless Queen
Joanna II of Naples adopted and named him as heir to the Kingdom of Naples, and Alfonso went to
Naples. Here he hired the
condottiero Braccio da Montone with the task of reducing the resistance of his rival claimant,
Louis III of Anjou, and his forces led by
Muzio Attendolo Sforza. With Pope
Martin V supporting Sforza, Alfonso switched his religious allegiance to the Aragonese
antipope Benedict XIII. When Sforza abandoned Louis' cause, Alfonso seemed to have all his problems solved; however, his relationship with Joanna suddenly worsened, and in May 1423 he had her lover,
Gianni Caracciolo, a powerful figure in the Neapolitan court, arrested. After an attempt to arrest the queen herself had failed, Joan called on Sforza who defeated the Aragonese militias near
Castel Capuano in Naples. Alfonso fled to
Castel Nuovo, but the help of a fleet of 22 galleys led by
Giovanni da Cardona improved his situation. Sforza and Joanna ransomed Caracciolo and retreated to the fortress of
Aversa. Here she repudiated her earlier adoption of Alfonso and, with the backing of Martin V, named Louis III as her heir instead. The duke of Milan,
Filippo Maria Visconti, joined the anti-Aragonese coalition. Alfonso requested support from Braccio da Montone, who was besieging Joanna's troops in
L'Aquila, but had to set sail for Spain, where a war had broken out between his brothers and the
Kingdom of Castile. On his way towards Barcelona, Alfonso sacked
Marseille, a possession of Louis III. In late 1423 the Genoese fleet of Filippo Maria Visconti moved in the southern
Tyrrhenian Sea, rapidly conquering
Gaeta,
Procida,
Castellammare and
Sorrento. Naples, which was held by Alfonso's brother, Pedro de Aragon, was besieged in 1424 by the Genoese ships and Joanna's troops, now led by
Francesco Sforza, the son of Muzio Sforza (who had met his death at L'Aquila). The city fell in April 1424. Pedro, after a short resistance in Castel Nuovo, fled to
Sicily in August. Joanna II and Louis III again took possession of the realm, although the true power was in the hands of
Gianni Caracciolo.
Second attempt An opportunity for Alfonso to reconquer Naples occurred in 1432, when Caracciolo was killed in a conspiracy. Alfonso tried to regain the favour of the queen, but failed, and had to wait for the death of both Louis (at Cosenza in 1434) and Joanna herself (February 1435). In her will, she bequeathed her realm to
René of Anjou, Louis III's younger brother. This solution was opposed by the new pope,
Eugene IV, who was the feudal overlord of the Kingdom of Naples. The Neapolitans having called in the French, Alfonso decided to intervene and, with the support of several barons of the kingdom, captured
Capua and besieged the important sea fortress of Gaeta. His fleet of 25 galleys was met by the Genoese ships sent by Visconti, led by
Biagio Assereto. In the
Battle of Ponza that ensued, Alfonso was defeated and taken prisoner. In Milan, Alfonso impressed his captor with his cultured demeanor and persuaded him to let him go by persuading that it was not in Milan's interest to prevent the victory of the Aragonese party in Naples. Helped by a Sicilian fleet, Alfonso recaptured Capua and set his base in Gaeta in February 1436. Meanwhile, papal troops had invaded the Neapolitan kingdom, but Alfonso bribed their commander, Cardinal
Giovanni Vitelleschi, and their successes waned. In the meantime, René had managed to reach Naples on 19 May 1438. Alfonso tried to besiege the city in the following September, but failed. His brother Pedro was killed during the battle. Castel Nuovo, where an Aragonese garrison resisted, fell to the Angevine mercenaries in August 1439. After the death of his condottiero
Jacopo Caldora, however, René's fortune started to decline: Alfonso could easily capture
Aversa,
Salerno,
Benevento,
Manfredonia and
Bitonto. René, whose possession included now only part of the
Abruzzi and Naples, obtained 10,000 men from the pope, but the cardinal leading them signed a truce with Alfonso. Giovanni Sforza came with a reduced corps, as troops sent by Eugene IV had halted his father Francesco in the
Marche. Alfonso, provided with the most impressive artillery of the times, again besieged Naples. The siege began on 10 November 1441, ending on 2 June the following year. After the return of René to Provence, Alfonso easily reduced the remaining resistance and made his triumphal entrance in Naples on 26 February 1443, as the monarch of a pacified kingdom. Alfonso then reunited under his dominion the kingdoms of
Naples and
Sicily, divided since the
Sicilian Vespers. After the personal union, he began to call himself
Rex Utriusque Siciliae; this was then used by other kings and his successors who ruled over those territories. ==Art and administration==