Philip I of Castile

Philip I of Castile
July 22, 1478 – September 25, 1506

Philip I of Castile was born on July 22, 1478, in the Netherlands. His father, Maximilian, was the son of Holy Roman Emperor Frederick III and a member of the Austrian Hapsburg dynasty. His mother, Marie, was the French Duchess of Burgundy. Two years before Philip’s birth, Marie faced pressure from King Louis XI of France to marry his heir, Charles. Through their marriage, Louis had hoped to add Burgundy’s vast territories to his kingdom. However, Marie resisted and instead married Maximilian, which gave the Hapsburgs a foothold along the French border.

In 1482, Marie died after falling from a horse. As a result, Philip succeeded his mother as duke of Burgundy. Since he was only four, Maximilian acted as his son’s regent and ruled on his behalf. As the 1480s progressed, France became more forceful in its efforts to seize Burgundy. Alarmed at France’s aggression, Maximilian allied himself with the Spanish monarchs Ferdinand and Isabella. The king and queen also feared French aggression and agreed to seal their pact through a double marriage.


As part of their arrangement, Philip would marry Ferdinand and Isabella‘s daughter, Joanna. In turn, the duke’s younger sister, Margaret, married Joanna’s older brother, John. At the time, the Spanish princess wasn’t expected to inherit her parent’s thrones. Despite this, Philip became interested in the idea of becoming the king of Castile someday.

Juana of Castile
Joanna of Castile

In 1496, Philip married 16-year-old Joanna. Although the marriage started passionately, it soon cooled. It quickly became apparent that Philip only valued his wife for her lineage. As a result, Philip often neglected Joanna, which only worsen her already fragile mental health. However, Joanna deeply loved Philip and flew into a rage whenever she discovered his cheating. Despite their unhappy union, the couple produced six children in under a decade.

Unexpected Succession

During the late 1490s, events began to play out in Philip’s favor. In 1497, Ferdinand and Isabella’s only son, John, died. Their new heir, princess Isabella, would die the following year after giving birth. Her son, Miguel, later died in 1500. Within three years, Joanna had quickly risen in the Spanish succession to become her parent’s heir. To Philip’s delight, he now had a chance at becoming king.

On November 26, 1504, Queen Isabella died. In her will, she left the throne of Castile to Joanna and allowed Ferdinand to act as regent. Seeking to capitalize on his wife’s new position, Philip and Joanna departed for Spain in early 1506. However, their voyage wouldn’t be easy. As they traveled across the sea, a storm caused their ship to go off course and land in England. Upon their arrival, the English king, Henry VII, welcomed the royal couple and had them stay at his court.

Henry VII of England
Henry VII of England

During their time in England, Henry VII kept the royal couple hostage. The king saw their arrival as a perfect opportunity to further his agenda. To this end, Henry forced Philip to agree to a trade treaty that benefited England over the Netherlands. Next, the king made the duke agree to support his efforts in capturing his enemies abroad. After several months, Henry finally released the royal couple and they resumed their journey to Spain in April.

Power Struggle

Upon arriving in Spain, Philip quickly came into conflict with his father-in-law over Castile’s throne. In her will, Queen Isabella had left her throne to Joanna only. Aware of her son-in-law’s ambition, the queen prohibited him from being crowned king. In Joanna’s absence, Ferdinand had ruled on Joanna’s behalf. Both men publicly accused each other of not acting in Joanna’s best interests. However, Ferdinand and Philip didn’t actually care about Joanna, just over who controlled Castile’s throne.

Philip eventually rallied enough Castilian support and raised an army. In turn, Ferdinand was forced to back down. On June 27, 1506, both men met to negotiate Ferdinand’s withdrawal from Castile. After his father-in-law departed, Philip assumed control over the kingdom. Claiming his wife was too mentally unstable to rule, Philip consolidated his power, and became King Philip I of Castile.

Premature Death

At last, Philip I of Castile had achieved his dream of becoming a Spanish king. However, his reign would be short-lived. As the king focused on organizing his administration, he began suffering from a fever. Over the next few months, Philip’s health steadily declined. Finally, on September 25, 1506, the 28-year-old king succumbed to his illness and died in Burgos. Despite horribly mistreating her throughout their marriage, Joanna mourned her husband’s early passing.


Philip I of Castile’s reign was short yet important in Spanish history. By becoming king, Philip laid the groundwork for the rise of Habsburg power in Spain. Through his son, Charles, the Habsburgs gained control of a united Spain after Ferdinand’s death in 1516. After becoming King Charles I, the Spanish Habsburg dynasty would be firmly established. From then on, Philip and Joanna’s descendants would rule Spain for close to 200 years.


Curtis, B. (2013). The Habsburgs: The History of a Dynasty. New York, NY: Bloomsbury.

Philip I. (n.d.). Retrieved March 29, 2021, from


Andy Tree

I'm a European history enthusiast who seeks to share his passion with others. I hope to inform and inspire readers with my posts!

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