Battle of Epila

Date	July 21, 1348
Location	Épila (Zaragoza)
Result	Decisive Victory for King Peter IV of Aragon

Belligerents

Union of Aragon

Peter IV of Aragon

Commanders and leaders

Ferdinand of Aragon
Juan Ximénez de Urrea, Lord of Biota

Don Lope de Luna.

Strength

15,000

The Battle of Épila was fought on July 21, 1348 near Zaragoza, in what is now Spain, between the supporters of the Union of Aragon and King Peter IV, led by Don Lope de Luna. This battle was the culmination of a long confrontation between a large segment of the nobility and the people of Aragon against the king, ending with the decisive defeat of the Union.

The start of direct conflict between the King of Aragon and much of the nobility and the towns of the kingdom went back to the year 1282, following the conquest of Sicily by Peter III and his excommunication by Pope Martin IV and subsequent Aragonese Crusade. To achieve more effective pressure on the king and protect each other, the nobility of Aragon signed the Oath of the Union, in which they pledged support for each other against the king of Aragon in the event he attempted to undermine their privileges. The first noble rebellion was later expanded to include the Union of Aragon and major cities, including the city of Zaragoza, capital of the Kingdom of Aragon.

Following the meeting of the Cortes in Zaragoza in 1283, Peter III was forced to accept the demands of the General Privilege of the Union, which expanded in 1287 during the reign of his son Alphonso III regarding the privileges of the Union.

Peter IV had become king of Aragon in 1336, following the death of his father Alfonso IV. His first major domestic problem occurred in 1347 with the reactivation of the Union of Aragon. The original purpose of the confrontation was in Peter IV's decision to acknowledge his daughter Constance as heiress to the Crown of Aragon, which infringed the rights of the Infante James, his own brother. As acting Governor of Aragon, James immediately went to Zaragoza to seek the support of the Aragonese nobility against the royal decision. The rebelling nobles again swore allegiance to the Union in support of the Infante movement; to which the majority of municipalities soon joined, including the capital. There was also a similar Union organized in the Kingdom of Valencia.

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