Isabella of Castile: a brief guide to the medieval queen

When Henry ascended the Castilian throne in 1454, she and her mother were moved to a humble country castle with only the most basic provisions, probably because the new king saw them as a threat. The princess whiled away her hours with her mother, who firmly instilled the Catholic fear of God into her daughter.

• Was Isabella I of Castile Europe’s greatest queen?

Over the years, opposition to Henry’s rule grew. The kingdom’s noblemen desired more power, and believed that the solution was to have a monarch who owed his or her position to them. When they rallied around Isabella as their new figurehead, she found herself thrust into the limelight. But the wise princess favoured diplomacy, and reached a settlement with Henry. In gratitude, he named Isabella the heir to the throne.

• Game of Queens: when women ruled Renaissance Europe

Isabella's secret marriage

Though Henry had tried several times to create political unions by marrying off his sister, Isabella only had eyes for one man – Ferdinand of Aragon. The pair had been betrothed when Isabella was just six, as Henry had been keen to ally with the neighbouring kingdom of Aragon. However, as Ferdinand’s father grew more powerful, he no longer needed the security and withdrew from the arrangement.

Despite this, Isabella and Ferdinand were secretly wed in 1469, and made a crucial prenuptial agreement that they would rule Spain as equals. An added bonus was that as rulers of Castile and Aragon, their marriage would unite two of Spain’s most powerful kingdoms.

When Isabella was crowned on 13 December 1474, she was not without enemies. Some maintained that Henry’s daughter, Joanna, was the rightful ruler. The King of Portugal, Afonso, quickly decided to betroth himself to Joanna and launched an invasion of Castile. So, Isabella and Ferdinand’s early reign was consumed with fighting this civil war, eventually sending Afonso packing back to Portugal.

• DID YOU KNOW? The betrothal of Catherine, the daughter of Isabella of Castile and Ferdinand of Aragon, and Arthur, the Prince of Wales and son of King Henry VII and Elizabeth of York, signalled a pivotal alliance between the kingdoms of England and Spain

Having cleared the path of their foes, the ‘Catholic Monarchs’ (as they would become known) set about rejuvenating their divided nation. In 1482, they led a military campaign on the Moorish city of Granada, the last remnant of the Muslim conquest of Spain.

The queen personally took an interest in military matters, and even moved the government a few miles away from the battle site. Eventually, in 1492, they won out and expelled the Muslim caliphate from Spain altogether. Now they controlled a vast expanse of territory, and it looked as if the entire Iberian Peninsula could be united.

When Isabella was crowned on 13 December 1474, she was not without enemies

Hernando del Pulgar, a 15th-century Jew who converted to Catholicism, said of Isabella: "She was very inclined to justice, so much so that she was reputed to follow more the path of rigour than that of mercy, and did so to remedy the great corruption of crimes that she found in the kingdom when she succeeded to the throne."

• Did the Age of Exploration bring more harm than good?

1492 would prove a big year for Isabella’s reign. The Italian explorer Christopher Columbus visited the queen and Ferdinand at the beautiful Alhambra palace, seeking royal approval for his planned voyage to India. Once he gained their support, he went on his way, only to stumble upon the Americas instead. Upon his return, he presented the monarchs with Native American slaves as a gift, much to Isabella’s horror. She immediately demanded that they be released, and ruled that no native could be enslaved as they too were her subjects. Sadly, these policies were rarely respected.

Isabella and the Spanish Inquisition

While these momentous events were taking place, a sinister policy guided by Islamophobia and anti-Semitism was ravaging the nation. Early on in their reign, as a plot to unify Spain religiously as well as politically, Isabella and Ferdinand had forced a number of Muslims and Jews to convert to Catholicism.

They then began the notorious Spanish Inquisition, an attempt to root out so-called ‘heretics’ from the ranks of new Christians. The scale of torture, executions and pillaging was completely unprecedented.

In 1492, all Jews were evicted from the Catholic Monarchs’ territory, given only three months to leave and forbidden from taking anything valuable with them. Spain’s newly acquired position as a world power was weakened, since the Jews formed a large part of the nation’s economy. The loss of such a vital part of Spanish society took its toll on Isabella’s reign, as did a number of personal tragedies she faced.

The scale of torture, executions and pillaging was completely unprecedented

In 1497, her only son and the heir to the throne, Juan, died before he reached the age of 20. To rub salt in her wounds, Isabella’s 27-year-old daughter died in childbirth, followed suit by Isabella’s baby grandson two years later.

The queen died in 1504, and Ferdinand continued to rule Castile as regent for their daughter Joanna, uniting Spain with his conquest of Navarre. The impact of her legacy on Spain was significant – as well as her foreign policy, the capable ruler had managed to restore law and order to a nation of bandits, reformed the Church, greatly improved Spain’s military, and repaired its financial system. Isabella remains one of Spain’s most revered monarchs.

This article was first published in the December 2017 edition of BBC History Revealed