The Struggle for Control of Iberia between Portugal, Castile, and England

While Portugal, Genoa, and Venice aimed their sights on exploring Africa, England warred with France. The Hundred Years War between the countries had started in 1337 and would continued until 1433. To make things more complicated for everybody, in 1378, the Roman Catholic Church split in two. For the next seventy years, there were two popes and sometimes three. The Portuguese, English, and the king of Castile sided with the pope in Rome, while the French and a pretender to Castile’s throne sided with the pope in France. This will lead to the very important Treaty of Windsor that England and Portugal will sign in 1386. Let us explain.

Two Popes

Some seventy years earlier, in 1305, the Church elected a Frenchman to be the pope, Pope Clement I. Clement I refused to move to Rome. In 1309, he moved the papal court to Avignon, where it remained for sixty-seven years under seven consecutive French popes, all strongly supervised by the French crown.

Finally, in 1377, the seventh Avignon pope, Gregory XI, moved the papal court back to Rome. But then Gregory XI complicated things again when he died the following year. The Church elected a new pope, Pope Urban VI (r. 1378–1389), who came from the Kingdom of Naples south of Rome. But after five months of his overly violent leadership, the French cardinals declared Urban to be unfit, antichrist, and possibly mad. They annulled his election and elected Clement VII (r. 1378–1394) to replace him.

That was not OK with the Roman contingent of the Church. They refused to release Urban VIfrom the papacy and exchange him for Clement VII. While France, Castile, and Scotland supported the schismatic pope Clement VII(1) in Avignon; England and the Roman contingent stayed loyal to Urban VI in Rome.

The only part about this you need to remember is that European monarchs and the Church were divided into two teams.

Two Kings of Castile

As if that were not enough to confuse the humble scholar, Castile was also a house divided. King Alfonso XI had died in 1350, and two of his sons warred about succession to his throne. The awkward situation lasted forty years. And while all this was going on, few people paid attention to exploring the Ocean Sea.

At first Alfonso’s legitimate son, Pedro, became king. [This Castilian Pedro should not be confused with the Portuguese Pedro who loved Inês.] Pedro was Alfonso’s son by his wife Maria of Portugal. But, as we mentioned in the story about the Portuguese Pedro, King Alfonso of Castile tossed Maria of Portugal out of his court in favor of a charming and still quite fertile widow named Eleanor de Guzmán. Eleanor remained Alfonso’s mistress until the end of his life and together they had twelve illegitimate sons. The oldest surviving son from that litter, Henry of Trastámara, thought he should be king instead of his half-brother, Pedro. [Historians call people like Henry, who claim to be king when they are not, pretenders to the throne.] Here is a family tree to help you sort this out.

Getting back to our teams, King Pedro of Castile, who belonged to the House of Burgundy, sided with the English, the Portuguese, and Pope Urban VI in Rome. Henry of the House of Trastámara sided with the French and Pope Clement I in Avignon.

Enter England

The King of England during all of this was Edward III of the House of Plantagenet – the same Edward III for whom the Inventio Fortunatae was written in the 1360s, and who was considering adding Iceland and Greenland to his kingdom. Edward and his wife Philippa of Hainault [a province in Belgium(2)] had eight sons. At this point in the story, 1368, four sons still lived. The first three will participate in this drama:

  1. Edward, known as the Black Prince (1330-1376), heir apparent
  2. John of Gaunt, the Duke of Lancaster (1340-1399)
  3. Edmund of Langley, the Earl of Cambridge (1341-1402)
  4. Thomas of Woodstock (1355-1397)

King Edward III entered the conflict when Henry of Trastámara’s fleet ganged up with the French fleet to bully the English merchant vessels along the English channel. Edward sent his oldest son, Edward the Black Prince, to fight alongside Pedro of Castile against the French

Edward the Black Prince and King Pedro won the first round. Trastámara escaped and fled to France, and then to Aragon, where he gathered a new army.

In 1369, Trastámara challenged Pedro to a new battle that was to take place in Montiel [located on the map above]

Under the guise of negotiation, Trastámara met with Pedro in Pedro’s tent. But instead of “parleying,” Trastámara killed Pedro “with his own hands.” The records are not clear about how Henry killed Pedro – by strangulation, by stabbing, by slaying him with a sword, or what. Whatever method, Henry Trastámara the Pretender grabbed the thrones of Castile and León for himself.

Pedro left behind two daughters: Constance, age fifteen, and Isabella, age fourteen. After Henry killed Pedro, Edward the Black Prince took Constance and Isabella into his protection and transported them to England. Several years later, Constance and Isabella will marry brothers of Edward the Black Prince, uniting England and Castile’s monarchy. But, we are getting ahead of ourselves.

John of Gaunt, Duke of Lancaster

First we need to tell you about the Plantagenet prince John of Gaunt, the Duke of Lancaster. John of Gaunt is one of those historical figures who are seldom mentioned in high school history books because their stories would make the books too long. Such figures were hugely influential, but they played from the sidelines. It was John of Gaunt, the people he surrounded himself with, and his influence on his daughter, Philippa, that gave the flavoring to this soup.

John of Gaunt was born in Ghent, Belgium, hence his name. He was the fourth son of King Edward III. Ten years earlier, in 1359, when he was nineteen, John had married fourteen-year-old Blanche of Lancaster, the daughter and heir of England’s wealthiest fiefdom. The Duke of Lancaster, Henry of Grosmont, was also of royal Plantagenet descent. After Henry of Grosmont died, John became the Duke of Lancaster, still the wealthiest fiefdom.

The estate where John and Blanche of Lancaster lived was called the Savoy. [There is a reason a very fancy hotel built on the former site kept the name.] The palace rivaled the king’s castles in splendor. Besides being wealthy, John of Gaunt was a very learned man. He and Blanche filled their court with well educated people. Gaunt was a protector of John Wycliffe, who was later condemned to hang for creating the first English translation of the Bible before it could be translated legally. [Wycliffe died of illness before the courts could hang him.]

Geoffrey Chaucer, the author of the Canterbury Tales, was another member of Gaunt’s entourage. Eventually Chaucer tutored John of Gaunt’s two daughters and one son. Chaucer wrote a book for his own son on how to use an ancient and very complicated device for finding direction and telling time called an astrolabe. He also taught Blanche how to use it. [We have already promised to describe this navigation tool later.] Chaucer was very found of his patroness. When Blanche died prematurely in 1368 at the age of twenty-three, he wrote: The Book of the Duchess to commemorate his Fair Blanche of Lancaster. Blanche was survived by her three children: Philippa, Elizabeth, and Henry. Philippa will become the Queen of Portugal and Henry will become the King of England.

Three years later, in 1371, thirty-one-year-old John of Gaunt, Duke of Lancaster, married as his second wife, the above mentioned seventeen-year-old Constance of Castile, the eldest of King Pedro of Castile’s two daughters who had fled to England with Edward the Black Prince after Pedro was murdered by his half-brother Henry of Trastámara.

John of Gaunt did not honor Henry of Trastámara as the legitimate king of Castile and León. As far as John of Gaunt was concerned, he, as Constance’s new husband, was Castile and León’s new king. As the pretender to the thrones, he began making plans for taking his seats.

In 1376, Edward the Black Prince, heir apparent to England’s throne, died, preceding his father, Edward III. [In other words, the Black Prince never got to be king.] Edward III died a year later, in 1377, and the new heir apparent, the Black Prince’s son, Richard, became king as Richard II.

There was a hitch. Richard II was only nine years old. He was placed under the guardianship of John of Gaunt, who, as the next prince in line after Edward the Black Prince, became the Prince Regent. From 1377 to Richard II’s majority at age thirteen in 1381, John of Gaunt carried out the responsibilities of the King of England.

In 1372, Constance of Castile’s seventeen-year-old sister, Isabella, married John of Gaunt’s younger brother, Edmund of Langley, who was the Duke of York and the Earl of Cambridge. That made Isabella the Duchess of York and tightened the connection between England and the House of Burgundy branch of the Castilian monarchy.

Now let us go back to Castile. In 1379, five years after the marriage of Constance to Edmund in England, Henry of Trastámara died leaving his son Juan I [John I in English] to inherit the thrones of Castile and León. With Henry of Trastámara dead, John of Gaunt needed to battle with Juan I if he still coveted the thrones of Castile and León.

Juan I of Castile made the first move. The Castilians will never be content leaving Portugal as an independent country. In 1381 Juan prepared to attack Portugal. King Fernando of Portugal asked England for help, which gave John of Gaunt the opportunity he was looking for. Busy in his position as Prince Regent, he sent his younger brother Edmund [husband of the other Castilian princess] and a force of English soldiers to fight in his place.

England had two incentives for supporting Portugal:

  1. The defeat of Juan I of Castile would free up the thrones of Castile and León for John of Gaunt.
  2. As part of the deal, Fernando of Portugal promised Edmund of Langley that Edmund’s son, six-year-old EDWARD Langley, would marry Fernando’s eight-year-old daughter and only surviving child Beatrice (1373-1420). [You might remember her. She was the daughter of the adulteress Queen Leonor and, possibly, her lover Andeiro. However, Beatrice was officially recognized as the daughter of Fernando, and if Edward Langley married her, he would be in line to the Portuguese throne when Fernando died. [I told you this would make you dizzy.]

Put another way, if everything went well for the English, John of Gaunt would become King of Castile and León, and his nephew, Edward, would become King of Portugal.

But things did not turn out that way. The Castilians thrashed the Portuguese along Portugal’s eastern front. Not knowing what to do next, Edmund of Langley hung out with his forces in western Portugal, where his bored armies pillaged the local farms and caused trouble with the townsfolk. The Portuguese were glad to see them return to England. Fernando withdrew his promise to marry Beatrice to Edmund’s son Edward.

Alienating the English even more, in 1383, King Fernando of Portugal switched sides and promised Beatrice, now ten years old, in marriage to Juan I of Castile. [Juan’s wife, Eleanor of Aragon, had died the year before, in 1382.] The wedding between Beatrice and Juan I took place on May 14, 1383.

Juan I of Castile thought it was only a matter of time before King Fernando of Portugal died and he, Juan, would assume the throne as Beatrice’s husband and unite the Iberian Peninsula as King of Castile, León, and Portugal. But that did not happen, either.


  1. And his successor Benedict XIII.
  2. This Belgian province was in Walloonia, which would become Protestant, and from where the Walloons left and settled Brooklyn, New York.
  3. Pope Urban encouraged England and Portugal’s fight against the French and the Castilians because it meant they were fighting against the supporters of his rival, the schismatic Pope Clement.

Next article: House of Avis