The Mudejars.
Political background. Until the disintegration of the caliphate of Córdoba in 1031, Muslims ruled the Iberian Peninsula up to the River Duero valley and the River Ebro valley to the Mediterranean coast, south of Barcelona. They called this land al-Andalus.

After 1031, al-Andalus split into numerous fragmented kingdoms or small emirates/states called taifas (“parties” or “factions”). With time, most taifas were absorbed or defeated by their larger Muslim neighbours, until there remained about six grouped around large cities: Zaragoza, Valencia, Toledo, Badajoz, Seville and Granada.
Politically weak and frequently at odds with each other, even to the point of allying themselves with Christian kingdoms against their fellow Muslims, these taifa kingdoms eventually sought help from fellow Muslims in the Maghreb (North West Africa) against the advancing Christians.
The end of Muslim domination was in sight, and came in 1212 with the defeat of the Almohad army at the battle of the Navas de Tolosa (1212) just south of the Sierra Morena. This was followed by the rapid, domino-like collapse of the taifas that made up what was left of al-Andalus. Three rival Christian kingdoms spearheaded the drive, León, Castile and Aragón.
The taifa of Badajoz fell in 1230 to the Leonese; Córdoba (1236), Seville (1248) and the Guadalquivir valley, as well as Murcia (1243) were taken by the Castilians, while the taifa of Valencia (1238-45) went to the Aragonese. That left only the taifa of Granada, which retained its independence as kingdom until 1492.

By mid-way through the 13th century, then, we have the reverse of what existed between 711 and 1031 when Muslims ruled most of the peninsula: most of it was now in Christian hands. During the period of Muslim domination, there were Christians (and Jews) who remained under Moorish jurisdiction; the Christians are known as Mozarabs (mozarabes) from the Arabic musta’rib, meaning “Arabised,” i.e. Christians who took on the external trappings of Muslims, adopting Muslim clothes, eating the same diet and even speaking Arabic.
As the Christian kingdoms advanced south, there were Muslims who remained in the newly-conquered Christian territory; these are the Mudejars (mudéjares), from the Arabic al-mudajjar, “people allowed to remain.”
The heaviest concentration of Mudejars was in the kingdoms of Navarre, Aragón and Valencia, reflecting the path of Islamic conquest and heaviest settlement in the 8th century.
In Castile, they were, generally speaking, less prominent, and less so in Old Castile (modern Castile-León) than in New Castile (modern Castile-La Mancha). Population estimates are notoriously difficult to arrive at. For Aragón, for example, percentages range between 15% and 50%; in Valencia from approximately 30% to over 50% and as high as 75%.
Why did the Mudejars remain under Christian rule?
As Christian kingdoms expanded southwards, tens of thousands of Muslims stayed under Christian rule, despite being urged by their religious leaders to leave. The orthodox view held by Muslim religious leaders was that the Mudejars had an obligation to abandon the land of the infidel. Many did, but the fact that most did not points to factors beyond religion that governed their decision.
The Mudejars felt sufficiently comfortable under Christian because of the kind of accommodation that Muslims themselves had practiced when allowing Christians (i.e. Mozarabs) and Jews, as dhimmis, to practice their respective faiths and customs in al-Andalus. The role was now reversed, but Christians, Muslims (and Jews) were long accustomed to life in a pluralistic, multicultural society, involving the three great religions of the Middle East.
Probably the most persuasive reason for staying for the Mudejars were the rights they were guaranteed by municipal charters (fueros) set up by the Christians for newly-conquered towns. In addition to preserving their religion, laws, culture etc., they could in general buy, sell or hold property and had freedom of movement. They were, however, by the nature of their relationship with the Christians, second class citizens.
Still, their way of life did not change fundamentally; it was under different management, as it were. Where they lived mainly in the countryside they formed the majority in many villages and were able to lead their traditional lifestyle with little inconvenience. The same held in the cities, where they lived mostly in their own neighbourhoods.
They continued to eat the same foods, preferring rice, couscous, fruit, vegetables, over meat, bread and wine favoured by Christians. They cooked with olive oil, avoiding pork fat (lard) used by Christians. They spoke Arabic, although in Navarre and Aragón (where the taifa of Zaragoza was conquered in the early 12th century) the spoken language appears to have been lost by the 13th century. Valencia was different in that it was not conquered until 1238. Until then Arabic survived, bolstered by the size of the Mudejar community, contact with neighbouring taifas (Granada, Seville) and communication with Muslims of North Africa.
In more rural areas, clothing tended to be Moorish, with “flowing robes, turbans and hooded cloaks” (Carr 48). In the cities, Christian styles were popular with the Mudejar upper classes, although they were expected to refrain from wearing anything that would set them above their station as second class citizens: e.g. jewels, gold, brightly coloured silks or furs.
The Muslims of al-Andalus had a long tradition as skilled agriculture workers: e.g. farmers, horticulturalists, and irrigation experts. These skills were continued by the Mudejars and were very attractive to Christian employers and landowners especially in Aragón and Valencia.
Indeed, much of the economic well-being of Aragón and Valencia from the 13th to the early 17th centuries depended on the agricultural expertise of the Mudejars. Also highly valued among Christians were their frugality and work ethic, practices that led to sayings such as cuanto más moros, más ganancias (“more Moors, more profit”).
In cities such as Zaragoza, Toledo, Seville, Córdoba, the Mudejars lived mostly in their own neighbourhoods, aljamas, although their work as craftsmen, carpenters, dyers, tanners, shoemakers, potters, leather workers, smiths, armorers, gardeners, muleteers etc., brought them in daily contact with Christians and Jews. Mudejar farmers also sold their products in Christian markets. And there are recorded instances of Mudejars attending Mass with Christian friends or Mudejar musicians playing in churches during night vigils, to the consternation of church authorities.
They were very highly valued as builders, applying their skills as bricklayers, plasterers and woodworkers in the construction and decoration of churches (e.g. the famous towers of Teruel in Aragón) and palaces (some of the decorative work in the Reales Alcázares in Seville).

Mudejars could have no say, however, in the running of the towns they lived in, and were prohibited from proselytising in any way.
They themselves were subject to attempts at conversion, although as Alfonso X makes clear in his Siete Partidas (codfication of laws for Castile) in the 13th century, “Christians should seek to convert the Muslims and make them believe our faith … not by force or through bribery.” The same king, however, insisted that Mudejars (and Jews) had to join Christians in kneeling if they saw a priest carrying the Host in the street during a procession. Although the church always pressed its case, the fact that there were still so many Mudejars in Aragón and Valencia up to the 16th century is evidence of little success.
As second class citizens, the Mudejars experienced periods of tension and discrimination. In most places, they could not hold public office, and in law suits against Christians, they were obliged to forgo sharia law. This often resulted in cases going against them, since tribunals were made up of Christians. Mudejar farmers were subject to heavier taxes than their Christian counterparts. Mosques were routinely taken over by Christians, leaving the Muslim community without their place of worship and social centre.
The 13th Century.
The rapid collapse of al-Andalus in the 13th century fuelled Christian fears that the Mudejars would constitute a fifth column. Such fears were confirmed when, for example, insurgency by Mudejars in the Guadalquivir valley in 1264-66 was supported by Muhammad I of Granada and the Merinid emir from the Maghreb. This resulted in the expulsion of thousands of Mudejars, most of whom ended up in Granada or Morocco.
Earlier, the conquest of the taifa of Valencia in 1238-45 provoked rebellions in both the city of Valencia in 1255 and in surrounding areas (e.g. Montesa, Alcoy, south of Valencia). In this case, however, the Mudejars stayed in large numbers because their commercially-minded overlords wanted them to remain to work the land they now held.
Castile, on the other hand, suffered a severe lack of manpower to colonise/ resettle the land left unoccupied by the expelled Mudejars. The result was to encourage the expansion of a feature of Castilian agriculture: sheep farming, which required little manpower.
1492 and after.
On January 1, 1492, the city of Granada surrendered and with it came the end of al-Andalus. Nevertheless, the fall of Granada did not signal the immediate end of Islam in the peninsula. According to the terms of capitulation signed in 1492, Muslims were allowed to retain their religion, as well as their laws, customs and property. In other words, they added to the number of Mudejars in Spain.
However, the fervour of Francisco Jiménez de Cisneros, the second Archbishop of Granada, supported by the religious zeal of Queen Isabella of Castile, provoked an unsuccessful three-month rebellion in the mountainous Alpujarras region to the south of the Granada early in 1501.
The rebellion allowed the Christians to overrule the terms of capitulation in 1502 and enforce a clear choice upon the Muslims: exile or baptism. Perhaps half the population of 400.000 chose to be baptised, at which point they ceased being Mudejars and became nuevos cristianos convertidos de moros, a term eventually replaced by the word “Moriscos.” The same edict was applied to the Mudejars of Castile, but not to Navarre, Aragón and Valencia. But that’s another story.
Sources:
Barton, Simon A History of Spain 2nd ed. Basingstoke, Hampshire, New York 2009
Carr, Matthew Blood and Faith: The Purging of Muslim Spain New York, London 2009
Harvey, L. P Islamic Spain 1250-1500 Chicago, London 1992
Harvey, L. P Muslims in Spain 1500 to 1614 Chicago, London 2005
Kamen, Henry Spain 1469-1714. A Society in Conflict London, New York Longman 1983
Map of al-Andalus: http://commons.wikimedia.org/wiki/File:Espa%C3%B1a1037.jpg
Map of Spain 1212-1492: http://commons.wikimedia.org/wiki/File:Espa%C3%B1a1212_a_1492.jpg