The Union of Aragon, an anti-royalist movement…

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.