In the late Middle Ages the Crown of Aragon experienced a confrontation between the monarchy and the nobility similar to that which occurred in neighbouring Castile. As Roman law and its practitioners gained in influence, there were protests in both Aragon and Catalonia, and James I confirmed the customary law of Aragon in an assembly at Ejea in 1265. He also agreed that the justicia, a judge appointed by the king from the ranks of the knights rather than from among the professional jurists, should adjudicate litigation involving the nobles. A critical stage in relations between the crown and the nobles was reached during the reign of Peter III (the Great; 1276–85), the heir to Aragon, Catalonia, and Valencia (the kingdom of Majorca fell to the share of his younger brother James).
Peter III’s conquest of Sicily, where he reigned as Peter I, was the second major step in the Mediterranean expansion of Catalonia, marking the beginning of a long international struggle with serious domestic complications. Although the papacy had awarded Naples and Sicily to Charles of Anjou, Peter’s wife represented Hohenstaufen claims to them. Taking advantage of the Sicilian Vespers, a rebellion by Sicilians against Charles’s rule, Peter occupied Sicily in 1282. Pope Martin IV not only excommunicated and deposed Peter but also offered Aragon to a French prince. Seizing the opportunity created by these difficulties, the Aragonese nobles organized a union to uphold their liberties and in 1283 compelled the king to grant their demands, which were set down in the document known as the General Privilege. Peter agreed to convene the Cortes each year and confirmed the right of the justicia to hear the lawsuits of the nobility. He made similar promises in Valencia and Catalonia, where the allegiance of his subjects was more secure. After the pope proclaimed a Crusade, King Philip III of France led the Crusading army against Peter but failed to achieve success. Thereafter the disposition of Sicily remained the chief concern of Peter’s three sons.
Alfonso III (1285–91), who inherited the mainland dominions, and his younger brother James, who received Sicily, valiantly tried to overcome the formidable opposition of the pope, the king of France, and the house of Plantagenet (Anjou). Alfonso seized Majorca because his uncle James had aided the French during their Crusade against Aragon. Once again the Aragonese nobles challenged the king, forcing him in 1287 to confirm his father’s General Privilege and to permit the nobles to control the appointment of certain royal councillors. After succeeding his brother as king of Aragon, James II (1291–1327) tried to secure an unchallenged title to that kingdom by yielding his rights to Sicily in 1295 and returning Majorca to his uncle James. Pope Boniface VIII awarded Sardinia to James II as compensation. In 1302 the pope reluctantly agreed to accept the third brother, Frederick, who had been proclaimed as king of Sicily. The Catalan Company, a mercenary troop idled by the end of the Sicilian wars, transferred its activities to the Byzantine Empire and in 1311 gained dominion over the duchy of Athens. Although neither Sicily nor Athens came under the direct rule of the king of Aragon, they remained bastions of Catalan influence and power in the Mediterranean.
After securing a favourable alteration of his frontier with Murcia, James II occupied Sardinia in 1325. As Genoa disputed Aragonese rights there, his successors, Alfonso IV (1327–36) and Peter IV (the Ceremonious; 1336–87), were forced to wage a series of wars. Accusing his cousin, the king of Majorca, of disloyalty, Peter IV annexed Majorca permanently to the Crown of Aragon in 1343. In 1347 Peter provoked a constitutional crisis by naming his daughter as heir to the throne rather than his brother, the count of Urgel, who argued that women were excluded from the succession. The Aragonese union, which had been relatively inactive in the previous reign, again confronted the king and compelled him to confirm the privileges granted by his predecessors. The Valencian nobility also organized a union and exacted similar concessions. The devastation caused by the Black Death and the royalist victory over the Aragonese union at Epila in 1348 enabled Peter to dissolve the union and to annul its privileges. The union never again threatened the crown.
After mid-century, Peter I of Castile invaded the Crown of Aragon, prompting Peter IV to back Henry of Trastámara’s claims to the Castilian throne, but Henry subsequently refused to reward him with any territorial concessions. That disappointment was offset to some extent by the reincorporation of Sicily into the dominions of the Crown of Aragon in 1377. Peter IV remained neutral during the Great Schism, but his son John I (1387–95) acknowledged the pope of Avignon. Both John and his younger brother and successor, Martin (1395–1410), had to attend constantly to agitation and unrest in Sardinia and Sicily. When Martin died without immediate heirs, the Crown of Aragon faced an acute crisis. Claimants were not lacking, but none enjoyed wide popularity. The estates of Aragon, Valencia, and Catalonia appointed nine commissioners to meet at Caspe to resolve the issue. The Compromise of Caspe, announced in 1412, determined that Fernando de Antequera, brother of King Henry III of Castile, had the best claim to the throne by right of inheritance. The accession of Ferdinand I (1412–16), the first of the Trastámara dynasty to rule in Aragon, prepared the way for the eventual union of Aragon and Castile. By withdrawing obedience from the Avignonese pope Benedict XIII, Ferdinand helped to terminate the schism.
Alfonso V (the Magnanimous; 1416–58) opted to pursue ambitions in Italy and generally neglected his peninsular domains. After occupying the Kingdom of Naples in 1442, he hoped to lord it over the rest of Italy and to extend his influence and power into the eastern Mediterranean. A spirit of discontent fostered by his long absence from Aragon provoked a crisis during the reign of his brother, John II (1458–79). John inherited the mainland kingdoms as well as Sicily, while Ferrante, Alfonso V’s illegitimate son, obtained Naples. John had already added another kingdom to the Trastámara holdings when he married the queen of Navarre in 1420. By quarreling with his son, Prince Charles of Viana, he antagonized many and provoked the open hostility of the Catalans. Charles’s sudden death in 1461 led many to believe that he had been poisoned by John. Already restive because of economic and social uncertainties, the Catalans revolted and offered the principality to other potential rulers. Louis XI of France seized the opportunity to occupy Roussillon and Cerdagne, thereby laying the foundation for future enmity between France and Spain. By 1472 John II had suppressed the Catalan revolt; subsequently he aided his daughter-in-law Isabella in acquiring the Castilian crown. His son Ferdinand succeeded him as king of Aragon and Sardinia, and his daughter Eleanor inherited Navarre. Aragonese institutions and society
Aragon, Catalonia, and Valencia constituted the nucleus of the Crown of Aragon during the late Middle Ages. James II declared in 1319 that these three states formed an indissoluble union. At various times Majorca, Sicily, Sardinia, and Naples were added to, separated from, and finally reunited with the Crown of Aragon. Peter IV and the people of Valencia opposed a plan to dismember the kingdom of Valencia for the benefit of the king’s younger brother. When the Catalans revolted against John II and unsuccessfully tried to secede, the Aragonese federation faced the threat of dissolution, but it was able to hold together. Ever since Peter II had offered his dominions in fief to the papacy in 1204 several popes had intervened directly in Aragonese affairs and had even tried to dispose of the throne.