The anti-royalist Union of Valencia attacks the Jews of Murviedro on the pretext that they are serfs of the King of Valencia and thus "royalists".

The Union of Valencia was an anti-royalist movement in the Kingdom of Valencia begun in 1283 and lasting into the fifteenth century. The Union was formed in the aftermath of the formation of the Union of Aragon in October 1283. Its essential purpose was as a tool of the Valencian nobility to be used against the influence of Catalans and foreigners on the actions of the Crown. By 1285 the Unions had severely curtailed the powers of the king and were hindering his efforts in the War of the Sicilian Vespers and against the Aragonese Crusade that invaded Catalonia that year.

Sagunto is a municipality of Spain, located in the province of Valencia, Valencian Community. It belongs to the modern fertile comarca of Camp de Morvedre. It is suburb of Valencia located approximately 30 km (19 mi) north of the city center. Lies on the Costa de Valencia on the Mediterranean Sea.

Serfdom was the status of many peasants under feudalism, specifically relating to manorialism and similar systems. It was a condition of debt bondage and indentured servitude with similarities to and differences from slavery. It developed during late antiquity and the Early Middle Ages in Europe and lasted in some countries until the mid-19th century.

For the majority of the Middle Ages, Valencia was a constituent part of larger polities. From the time of the Muslim conquest of the Iberian Peninsula, Valencia was controlled by the Umayyad Caliphate in Damascus and the Emirate/Caliphate of Cordoba. Following the latter's collapse, Valencia became the seat of a Taifa state ruled by a succession of local dynasties from 1010 until it was conquered by Rodrigo Díaz de Vivar, El Cid, in 1095. He ruled until his death, when his widow swore fealty to Castile, but was forced out in 1102 and Valencia fell back under the control of a Muslim Caliphate.