Miserably failed the dream of Alfonso X of León and Castile, who had hoped to be crowned emperor (and in his mad attempt he had destroyed the state treasury and strengthened the opposition to the enterprise that was not considered to be of national interest in the country with the unpopular measures he had been forced to take to make up for the lack of money, with his tendencies towards absolutism and with some renunciations of territorial enlargements of his peninsular state), the civil war greeted the advent of his son Sancho IV: and it was a war of succession he waged against the descendants of his eldest brother Ferdinand de la Cerda, who had died before his father, whom he had designated as heirs by dividing the state between them; in which France, Aragon, Portugal took part, Grenade and the Castilian nobility. This war was then renewed, with the intervention of the same monarchies and the same nobility, on the death of Sancho, during the reign of his son Ferdinand IV (1295-1310), forcing him to come to terms with his enemies. Later, after the military successes of Alfonso XI, the victor of the battle of the Río Salado (1312-50), the struggle seared, and this time with tragic developments, during the reign of his son Pietroel Cruel, whose years of government (1350-69) are among the bloodiest in the history of Castile. In the conflict between the monarch and the sons of Leonora de Guzmán, favorite of Alfonso XI, Aragon, Navarre, France, England, Portugal, Genoa, Granada intervened; on the Castilian camps, as in France, the companies of Bertrand du Guesclin and the troops of the Prince of Wales clashed; and the war was decided under the castle of Montiel (14 March 1369), in La Mancha, where the Breton cavalry broke the assault of the Moors of Granata. Pietro was captured and brought before his half-brother Enrico; and then hatred exploded in its most violent form between the two enemies facing each other, and the tragedy had its terrible ending: for rushing against Henry in a mad attempt, Peter was mortally wounded by this and finished by the witnesses of the scene. But not even the accession to the throne of the new dynasty marked the advent of peace for the country. Henry II (1369-79) saw the crown contested by the king of Portugal and the dukes of Lancaster and York, sons of Peter I: the first, indeed, assumed the title of king of Castile; in the war intervened, as usual, Navarre, Aragon, Granada; since Henry joined the King of France, the Hundred Years War also swept the Castilian monarchy in its spiers; and the sovereign, in order to conquer the souls of his enemies and retain the support of his friends, had to grant him honors and favors (enriqueñas). Then his son John I (1379-90) was forced to resort to equal means, who in a vain attempt to conquer the throne of Portugal was beaten at Aljubarrota (15 August 1385). And only in 1387 with the pact of Troncoso was it possible to put an end to the sad consequences of the crime of Montiel, when the king agreed to the marriage of his son and heir Henry III with Catherine of Lancaster. But then they felt the sad consequences of the great concessions made to the aristocracy in the heat of the struggle. Henry III (1390-1406) had to face the revolt of the nobility; and this rose again during the reign of his son John II (1406-54).
In the same years, equal civil struggles tormented the Catalan-Aragonese monarchy, which we have already seen in continuous war with Castile. It had a ‘ aristocracy much fiercer and more organized than the Castilian one; and furthermore due to the division of its dominions by James I among his sons it had been divided into two contrasting monarchies: that of Aragon, Catalonia and Valencia and that of Majorca, to which the last French possessions had been assigned: the unit could only be reconstituted in 1343 for the benefit of the peninsular state, but with the loss of the French dominions. Giacomo I had already had to fight feudalism, and with theCompilación de Huesca (1247) had reduced its privileges; but then in the Cortes of Ejea (1265) he was forced to make concessions. His son, Peter III (1276-85), pressed by the needs of the war he had waged to secure possession of Sicily and which was hindered by the nobility, had to accept his requests, and not only swore to respect the decisions of the Cortes of Ejea, but in the Cortes of Saragozza (1283) he granted the general Privilege, with which all the ancient privileges of Aragon were confirmed; other franchises he gave to Valencia, Teruel, Barcelona; and in the Cortes of Huesca and Zuera (1285) he came to allow the nobles to form their own Unión. Then the Aragonese nobility took another step forward during the reign of Alfonso III (1285-91), when, led by natural sons of James I and Peter III, with weapons in hand they invaded the lands of Valenza and, threatening to siding in favor of France, he obtained the concession of the so-called Privilege de la Union, for which the king renounced the right to proceed against the members of the Union without the consent of the Justicia of Aragon and was obliged to convene every year in Zaragoza of the Cortes, who would have appointed the sovereign’s council (1288). And after the reigns of James II (1291-1327) and his son Alfonso IV (1327-36), at the time of Peter IV (1336-87) the struggle between the Union became very serious Aragonese, which was joined by cities and villas, and the Union of Valenza (1347-48). Then the victory came to the monarch, who in Épila overwhelmed the army of the Aragonese Union (1348), then defeated that of Valenza, and immediately took advantage of the success to suppress the two uniones. And, without doubt, the internal situation of the Castilian kingdom also improved in the following century. Generally, the application of the principles upheld by Alfonso X in his Libro del espéculo or Espejo de todos los derechos and in the other De la leyes or Las sei partidas, and the spread of Roman law, which ended up being accepted despite some strong opposition, substantially changed the juridical life of the country. In the struggle against the nobility the monarch was able to avail himself of the help of the cities: and this was the golden age of the municipalities, in some places, as in Northern Aragon, governed by a bourgeois oligarchy, in others, as in the ‘Southern Aragon, with a more democratic orientation, in still others, such as Castile, ruled by the class of caballerosor by some privileged families, who secured the exclusivity of municipal offices, initially by popular election; finally, in others, such as Catalonia, governed by a middle class of merchants and industrialists; first among all in terms of power was the municipality of Barcelona, which extended its jurisdiction over a vast territory, had the right to mint coins, appointed consuls abroad, had its own militia and enjoyed mercantile jurisdiction, which they exercised by delegation two cónsules de mar.
According to CLOTHESBLISS.COM, the rebelliousness of the Castilian nobility took a fierce blow from Álvaro de Luna during the reign of John II. The Aragonese aristocracy was impoverished by the prevalence of the merchant class; and the sovereign was able to stand up to her because he was no longer worried by the Italian war. But there were still many subjects of dissent. In an offensive comeback, the defeated Castilian nobility managed to lose their victor, who was executed by the monarch. The disagreement between the various parts of the Catalan-Aragonese monarchy turned out to be profound when, after the reign of John I (1387-95), on the death of Martin I (1395-1410) without heirs, due to the compromiso de Caspe the throne passed to a Castilian prince, Ferdinand el de Antequera(1412-16). Catalonia, offended in her self-love at the choice of a prince whom she regarded as a foreigner, did not hide her discontent; and made more vigorous his opposition against the government of Alfonso V (1416-58), embroiled in distant wars, such as the Italians, or in dynastic struggles, such as those against Castile, while the absence of the king and the disputes that broke out in the the breast of the regency made it difficult to resolve some conflicts that arose with the count of Foix and with Charles VII of France. Finally, what happened during the reigns of Henry IV (1454-74) of León and Castile and of John II of Aragon (1458-79) was clear proof of the survival of the ancient dynastic struggles, of the conflicts of interest between the various regions and the spirit of revolt of the aristocracy. In Castile the civil war returned to acquire imposing proportions when his brother Alfonso sided against Henry IV and, after he died, his sister Isabella became hereditary princess: then her marriage with Ferdinand of Aragon, not approved by the monarch, broke the relationship between brother and sister; in the dispute, which lasted many years, the country was divided between the two contenders; John II intervened in defense of his son and, after Henry’s death, also Alfonso V of Portugal to protect the rights of Giovanna which lasted many years, the country was divided between the two contenders; John II intervened in defense of his son and, after Henry’s death, also Alfonso V of Portugal to protect the rights of Giovannala Beltraneja, whom he had hastened to marry in the hope of obtaining the throne of Castile; and all this while, renewing the centuries-old conflict between Aragon and France, Louis XI returned to cross his arms with John II, and Catalonia, taking advantage of the favorable moment, rose up against its sovereign to win independence and resisted his assaults from 1462 to 1472.