Alfonso III of Aragon

Alfonso III, soon after assuming the Aragóneses throne, had conducted a campaign to reincorporate the Balearic Islands, which had been lost due to the division of the kingdom by his grandfather, James I of Aragon.

Thus, in 1285, he had declared war on his uncle, James II of Majorca, and conquered both Majorca (1285) and Ibiza (1286), effectively resuming suzerainty over the Kingdom of Majorca.

Charles of Salerno, the Angevin pretender, who is still held captive by the Sicilians, finally grows tired of his long captivity and signs a contract February 27, 128, in which he renounces his claims to the kingdom of Sicily in favor of James II of Aragon and his heirs.

Honorius IV, however, declares the contract invalid and forbids all similar agreements for the future.

While Honorius IV is inexorable in the stand he has taken towards Sicily, his relations towards Alfonso III of Aragon become less hostile.

Through the efforts of King Edward I of England, negotiations for peace are begun by Honorius IV and King Alfonso III.

Alfonso III of Aragón conquers  Minorca—until this time, an autonomous Muslim state (Manûrqa) within the Kingdom of Majorca—on January 17, 1287, the anniversary of which today serves as Minorca's national holiday.

Most of the island's Muslim inhabitants are enslaved and sold in the markets of Eivissa, Valencia and Barcelona; others become Christians.

The Union of Aragon, an anti-royalist movement among the nobility and the townsmen of the lands of the Crown of Aragon during the last quarter of the thirteenth century, forces Alfonso III to make concessions to the nobility.

The Union had its origin in the nature of the Crown of Aragon, incorporating various kingdoms at various times, but always Aragon and Valencia, as well as most of the Catalan counties, primarily Barcelona.

The various lands vied for the attention of the monarch and struggled to protect their privileges and their influence against the rise of any other.

At the same time, King Peter III was conquering Sicily and his Spanish dominions were neglected.

Eventually, Pope Martin IV called a crusade, the Aragonese Crusade, against Peter and his kingdom, dissolving his subjects of their oaths of fealty.

Peter had to exact heavy taxes in order to finance resistance to the "crusade" against him.

The nobles of the kingdom, believing they should have been consulted before any campaign to Sicily, formed the Union.

In 1283, the nobles and burgers of Aragon held a cortes in Zaragoza at which they swore to uphold each other's rights.

Within three months, the cortes of Catalonia swore a similar oath at Tarragona.

At both, Peter III had to recognize the ancient customs and fueros of the people and vow to summon the cortes annually.

This was known as the General Privilege (Privilegio general).

The Union had met at Zaragoza in December 1286, and then in January 1287 at Teruel.

After brief talks with Alfonso III in May 1287, the Union invades Valencia and fights some battles with the king's supporters until a Dominican prior from Zaragoza, Valero, organizes a meeting in Zaragoza for December 20.

The Union forces many royal concessions from the weak Alfonso, who grants them the Privilege of the Union (Privilegio de la unión).

The Privilege names the Union as the "true guardian of Aragonese law in the Crown's territories.

The Privilege devolves many royal functions to the lesser nobility and the Crown of Aragon will nearly into anarchy, especially during the reign of Peter IV.

Angevin monarch Charles II is released from four-years of captivity under the Treaty of Campofranco concluded between Aragon and Naples on October 27, 1288.

The leader of the pro-papal Guelph party in Italy, he will devote himself thereafter to attempts to reconquer the island of Sicily and to the dynastic interests of his family.

The Angevin Kingdom of Naples issues the first expulsion of Jews in southern Italy.

The General Privilege issued in 1287 by Alfonso III of Castile had ordained that the king could not proceed against any nobleman without the prior permission of the Justicia acting on the approval of the cortes.

This last was to be summoned annually (in November) to the city of Zaragoza.

If the king ever broke his terms of the Privilege, he need not be obeyed and no act against him was to be considered treason.

Thus, the king could be deposed by the nobles in extreme circumstances.

By January 1288, the Union is appointing the king's councilors.

Alfonso’s brother and successor James II will refuse to recognize the Privileges and, by the Act of Union, makes permanent the Crown of Aragon and the union of Aragon, Valencia, and Catalonia under one crown.

The Aragonese union will be imitated by a Union of Valencia.

James, ruler of Sicily, ascends the Aragonese throne as King James II at the death of his brother Alfonso III in 1291.

Alfonso’s reign has been marred by a constitutional struggle with the Aragonese nobles, which eventually culminate in the articles of the Union of Aragon—the so-called "Magna Carta of Aragon", which devolves several key royal powers into the hands of lesser nobles.

His inability to resist the demands of his nobles is to leave a heritage of disunity in Aragon and further dissent among the nobility, who increasingly see little reason to respect the throne, and bring the Kingdom of Aragon close to anarchy.

During his lifetime, a dynastic marriage with Princess Eleanor of England, daughter of King Edward I of England, has been arranged.

However, before meeting his bride Alfonso dies in in 1291 at the age of twenty-six and is buried in the Franciscan convent in Barcelona; since 1852 his remains have been buried in Barcelona Cathedral.