List of Alternate Monarchs and Aristocratic Lineage
- Thread starter Jonathan
- Start date
Because as per your own POD all of Charles and Isabella's children survive, making Juan and Manuel fourth and fifth-born sons respectively, they've got too many brothers ahead of them.
Edward VI's six wives [note: this is ASB]
Edward VI b. 1537 d. 1600
m. 1550 d. 1554 (died of childbirth issues) Jane Grey [a]
1a. Jane b. 1554
m. 1555 d. 1560 (died of childbirth issues) Cecilia of Sweden
2b. Margaret b. 1556
3b. Cecilia b. 1557
4b. miscarriage 1559
5b. stillborn 1560
m. 1561 ann. 1561 due to non-consummation Barbara of Hesse [c]
- no issue -
m. 1562 ann. 1570 due to consanguinity (in reality due to religious conflicts and mutual infidelity) Mary Queen of Scots [d]
6d. Henry IX b. 1562
7d. Mary b. 1564
8d. James VI b. 1566
9d. Edward b. 1569
m. 1570 d. 1573 (executed due to infidelity) Susan Bertie [e]
- no issue -
m. 1578 d. 1638 (outlived Edward and lived as queen dowager) Catherine Knyvett [f]
10f. Catherine b. 1581
11f. Thomas b. 1583
12f. miscarriage
13f. Cecily b. 1585
14f. stillborn
Edward VI b. 1537 d. 1600
m. 1550 d. 1554 (died of childbirth issues) Jane Grey [a]
1a. Jane b. 1554
m. 1555 d. 1560 (died of childbirth issues) Cecilia of Sweden
2b. Margaret b. 1556
3b. Cecilia b. 1557
4b. miscarriage 1559
5b. stillborn 1560
m. 1561 ann. 1561 due to non-consummation Barbara of Hesse [c]
- no issue -
m. 1562 ann. 1570 due to consanguinity (in reality due to religious conflicts and mutual infidelity) Mary Queen of Scots [d]
6d. Henry IX b. 1562
7d. Mary b. 1564
8d. James VI b. 1566
9d. Edward b. 1569
m. 1570 d. 1573 (executed due to infidelity) Susan Bertie [e]
- no issue -
m. 1578 d. 1638 (outlived Edward and lived as queen dowager) Catherine Knyvett [f]
10f. Catherine b. 1581
11f. Thomas b. 1583
12f. miscarriage
13f. Cecily b. 1585
14f. stillborn
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It’s if Spain continued to follow Salic Law and Fernando VII’s brother, Don Carlos, ascended to the throne instead of his daughter Isabel.
Assuming the POD is either a victory in the First Carlist War or Fernando never decides to push the Pragmatic Sanction that named Isabel II his heiress, that means that she'll marry Carlos VI (as planned, and thus butterflying anybody after Alfonso Carlos -who'd be Alfonso XII, he only tacked on the Carlos to avoid confusion with Alfonso XIII) . If Fernando dies with no children, Carlos VI will avoid his OTL death since that was caused by an outbreak of diphtheria or typhoid or somesuch in Trieste. But assuming we go all the way to Jaime III as OTL, there'll be no reason stopping him marrying Mathilde of Bavaria, since the main obstacle to that was her mother and Queen Regent Maria Christina of Spain.
Ferdinand will get Marguerite de Valois, Anna d'Este or some other French proxy in all likelihood. Magdalene's father was against any of his daughters marrying Karl V's sons because he thought that Karl would try to slide his feet under the table in the empire that way. Other option would be a Lorrainer girl like Anne of Lorraine, Dowager Princess of Orange
Will marry Anna d'Este (if his older brother doesn't) or some equally Italian girl
Or she can wed to the dukes of Savoy (Emanuele Filiberto), Ferrara (Alfonso II) or grand duke of Tuscany (she laughed the last proposal off)
Uh why? The nearest heir would be Don Carlos, then Maria of Guimaraes's brother.
Best-Case Scenario for the Catholic Monarchs
WI: Best-Case Scenario for the Catholic Monarchs. Juana la Beltraneja dies in 1472, before her father, and Henry IV is forced to recognize Isabella as his heir. This allows the couple to avoid the war with Portugal.
Ferdinand II of Aragon (1452-1516) m. Isabella I of Castile (1451-1524) [1]
1a. Isabella of Castile and Aragon (1470-) m. Edward V of England (1470-1492) [2]
2a. Juan III of Castile and Aragon (1473-1511) m. Catherine I of Navarre (1468 -) [3]
3a. Juana of Castile and Aragon (1475-) m. Alfonso VI of Portugal (1475-) [4]
4a. Ferdinand VI of Castile and Aragon (1476-) m. Louise of Savoy (1476-) [5]
5a. Alfonso, Duke of Cadiz (1477-) m. Elizabeth of Denmark (1485-) [6]
6a. Miguel of Castile and Aragon (1478-1482)
7a. Stillborn Daughter (1479)
8a. Maria of Castile and Aragon (1482-) m. Charles VIII of France (1470-) [7]
9a. Ana of Castile and Aragon (1482-1484)
10a. Catalina of Castile and Aragon (1485-) m. Ernest, King of the Romans (1486-1503) [8]
2a. Miscarried Son (1503)
[1] The reconquest of Granada still occurs. Butterflies call for a crusade against the Ottomans in the late 1490s/early 1500s. Eventually all of Greece and Constantinople are reconquered. In 1524, Jerusalem is finally taken from the Muslims. Isabella, old and frail, travels to the Holy City, and will die there. She will be buried in the Church of the Holy Sepulcher. Isabella manages to enforce her will in the Americas, and the Natives are treated much better, though smallpox is still rampant.
[2] Isabella, anglicized Elizabeth, and Edward have a harmonious and happy marriage. Edward is much like his father, tall, blonde, and broad, with a desire to war with the French. Isabella has a kindly and pious nature, which makes her very popular with the common people and nobility alike. Edward manages to take back Rouen in Normandy before he dies in battle. His wife, heavily pregnant upon his death, gives birth to a posthumous son. She is regent for the boy, until he dies, and continues to remain an important advisor to her daughter, England’s first undisputed Queen-Regnant, married to the heir to the Danish throne. Isabella will join her mother in the Holy Land, and will eventually be buried alongside her.
[3] Juan and Catherine seemed to have a cloud of bad luck always hanging over them. The two, betrothed since childhood, instantly disliked each other. Juan found Catherine to be unattractive, and Catherine found Juan argumentative and annoying. Out of their seven children, only three were born alive, and none made it past the age of eleven. Catherine was hated by the court for her snobbish and anti-social behavior, so she stayed mostly in Pamplona, separated from her daughters, who were raised and educated by their Castilian grandmother. Juan crusaded against the Ottomans, and has numerous affairs with many women. He officially had 11 illegitimate children, but he privately recognized as many as 30. Some historians have argued he probably had as many as fifty children. Catherine died in 1517, in a convent where she had been imprisoned after her brother-in-law had captured her kingdom.
[4] Juana was, from a young age, the most beautiful of the Aragon girls. She was also dignified and elegant, tall with strawberry blonde hair like her mother. Her marriage to Alfonso was normal for the period, and Juana took a particular interest in her children’s education. Juana herself was very intelligent and kept the largest library in the world at the time. She also hosted intellectuals and artists at the palace.
[5] If Juana was beautiful, than Ferdinand was cunning. As a child, he was known to play tricks on his siblings, and cause chaos for his nursemaids. He grew into an energetic, good-tempered, and handsome young man. His marriage to Louise of Savoy was largely a success, and the two, using Isabella’s fondness for her second son, carved out favors and land for their children. Louise was delighted when, one by one, her brother-in-laws children died. Ferdinand proved a popular and wise king, and Queen Luisa was praised for her beauty and for the festivities she hosted at court.
[6] Alfonso was somewhat of the black sheep of the family. His younger brother, Infante Miguel, had been given as an oblate, though he had died at the age of four after he caught cold. Isabella wished to offer her third son to the church, but Ferdinand insisted he remain in the secular world. Alfonso himself was lazy in his studies, preferring to write poetry and compose songs. He refused to marry on several occasions, probably because he was a homosexual. He also developed the nasty habit of being a drunk, and gambling. Because of all these unsavory rumors, Isabella and Ferdinand finally forced Alfonso to marry Danish Princess Elizabeth. Elizabeth desperately loved her husband, but her husband did not return her affections. After the birth of Enrique, heir to the Dukedom of Girona, the couple finally separated. A few years later, in 1517, it became clear that Alfonso had caught a sexual disease from one of his lovers. This disease would eventually kill him.
[7] Charles VIII marries Margaret of Austria in 1494. She dies giving birth to a stillborn daughter in 1498. Anne of Brittany would marry Richard, Duke of York and Normandy, and the two ruled over a joint Breton-Norman Kingdom. After Margaret died, Maria was sent to marry the widower. Charles and Maria did not love each other, but were at least friendly. Certainly they mist have been somewhat close, for the marriage would result in ten children.
[8] Catalina, the baby of the family, was a sweet and devoutly pious young woman. She would marry Ernest of Austria, the eldest son of Emperor Maximilian I and Elizabeth of York. Ernest had been promised the Holy Roman Empire as an inheritance. This caused some drama, because Philip, Maximilian’s eldest son from a first marriage, and also Duke of Burgundy, believed he should be heir. Ernest and Catherine were happy together during their brief marriage, but he two caught influenza in the spring of 1503, which killed Ernest and made Catalina miscarry their second child. When Philip became Emperor in 1509, he made a frequent point to bully and make fun of Elizabeth of York and Catalina. The two lived at a convent outside Vienna. Anne of York, Holy Roman Empress, was herself miserable, especially after her only child, Charles, died in 1512. Philip would die in 1516, childless. Ernest’s only child, daughter Elisabeth was ineligible to succeed, so Ernest’s younger brother, Fredrick, married to a Polish princess with a load of children, became Emperor. Elizabeth of York would return to court, dying in 1543. Catherine would stay at her convent, becoming a nun, and eventually abbess. She was extremely pious, and took care of the poor and sick in her hospitals. Several miracles, including healing, were attributed to her. She finally died in 1570, at the age of 85, miraculous for that time. In 1595, she was canonized as a Saint.
Ferdinand II of Aragon (1452-1516) m. Isabella I of Castile (1451-1524) [1]
1a. Isabella of Castile and Aragon (1470-) m. Edward V of England (1470-1492) [2]
1a. Elizabeth I of England (1486-)
2a. Jacquetta of England (1489-)
3a. Richard III of England (1492-1504)
2a. Juan III of Castile and Aragon (1473-1511) m. Catherine I of Navarre (1468 -) [3]
1a. Miscarried Daughter (1492)
2a. Isabella of Castile and Aragon (1492-1494)
3a. Maria of Castile and Aragon (1494-1505)
4a. Stillborn Son (1494)
5a. Miscarried Daughter (1496)
6a. Catalina of Castile and Aragon (1500-1511)
7a. Stillborn Daughter (1502)
3a. Juana of Castile and Aragon (1475-) m. Alfonso VI of Portugal (1475-) [4]
1a. Maria of Portugal (1493-)
2a. John III of Portugal (1494-)
3a. Miscarried Son (1498)
4a. Ferdinand, Duke of Beja (1502-)
5a. Alfonso, Archbishop of Guarda (1505-)
4a. Ferdinand VI of Castile and Aragon (1476-) m. Louise of Savoy (1476-) [5]
1a. Alfonso VII of Castile and Aragon (1495-)
2a. Isabella of Castile and Aragon (1495-)
3a. Ferdinand, Duke of Granada (1497-1499)
4a. Enrique, Archbishop of Burgos (1501-)
5a. Stillborn Daughter (1505)
5a. Alfonso, Duke of Cadiz (1477-) m. Elizabeth of Denmark (1485-) [6]
1a. Isabella of Cadiz (1503-)
2a. Alfonso of Cadiz (1507-1509)
3a. Miscarried Daughter (1510)
4a. Leonor of Cadiz (1510-1513)
5a. Stillborn Son (1511)
6a. Enrique, Duke of Cadiz (1511-)
6a. Miguel of Castile and Aragon (1478-1482)
7a. Stillborn Daughter (1479)
8a. Maria of Castile and Aragon (1482-) m. Charles VIII of France (1470-) [7]
1a. Isabelle of France (1500-1514)
2a. Miscarried Son (1501)
3a. Charles, Dauphin of France (1504-1508)
4a. Charlotte of France (1506-)
5a. Louis, Dauphin of France (1510-1517)
6a. Marie of France (1512-)
7a. Philippe VII of France (1512-)
8a. Jean, Duke of Berry (1515-1529)
9a. Stillborn Daughter (1518)
10a. Francis, Duke of Anjou (1518-1520)
9a. Ana of Castile and Aragon (1482-1484)
10a. Catalina of Castile and Aragon (1485-) m. Ernest, King of the Romans (1486-1503) [8]
1a. Elisabeth of Austria (1502-) -abbess-
2a. Miscarried Son (1503)
[1] The reconquest of Granada still occurs. Butterflies call for a crusade against the Ottomans in the late 1490s/early 1500s. Eventually all of Greece and Constantinople are reconquered. In 1524, Jerusalem is finally taken from the Muslims. Isabella, old and frail, travels to the Holy City, and will die there. She will be buried in the Church of the Holy Sepulcher. Isabella manages to enforce her will in the Americas, and the Natives are treated much better, though smallpox is still rampant.
[2] Isabella, anglicized Elizabeth, and Edward have a harmonious and happy marriage. Edward is much like his father, tall, blonde, and broad, with a desire to war with the French. Isabella has a kindly and pious nature, which makes her very popular with the common people and nobility alike. Edward manages to take back Rouen in Normandy before he dies in battle. His wife, heavily pregnant upon his death, gives birth to a posthumous son. She is regent for the boy, until he dies, and continues to remain an important advisor to her daughter, England’s first undisputed Queen-Regnant, married to the heir to the Danish throne. Isabella will join her mother in the Holy Land, and will eventually be buried alongside her.
[3] Juan and Catherine seemed to have a cloud of bad luck always hanging over them. The two, betrothed since childhood, instantly disliked each other. Juan found Catherine to be unattractive, and Catherine found Juan argumentative and annoying. Out of their seven children, only three were born alive, and none made it past the age of eleven. Catherine was hated by the court for her snobbish and anti-social behavior, so she stayed mostly in Pamplona, separated from her daughters, who were raised and educated by their Castilian grandmother. Juan crusaded against the Ottomans, and has numerous affairs with many women. He officially had 11 illegitimate children, but he privately recognized as many as 30. Some historians have argued he probably had as many as fifty children. Catherine died in 1517, in a convent where she had been imprisoned after her brother-in-law had captured her kingdom.
[4] Juana was, from a young age, the most beautiful of the Aragon girls. She was also dignified and elegant, tall with strawberry blonde hair like her mother. Her marriage to Alfonso was normal for the period, and Juana took a particular interest in her children’s education. Juana herself was very intelligent and kept the largest library in the world at the time. She also hosted intellectuals and artists at the palace.
[5] If Juana was beautiful, than Ferdinand was cunning. As a child, he was known to play tricks on his siblings, and cause chaos for his nursemaids. He grew into an energetic, good-tempered, and handsome young man. His marriage to Louise of Savoy was largely a success, and the two, using Isabella’s fondness for her second son, carved out favors and land for their children. Louise was delighted when, one by one, her brother-in-laws children died. Ferdinand proved a popular and wise king, and Queen Luisa was praised for her beauty and for the festivities she hosted at court.
[6] Alfonso was somewhat of the black sheep of the family. His younger brother, Infante Miguel, had been given as an oblate, though he had died at the age of four after he caught cold. Isabella wished to offer her third son to the church, but Ferdinand insisted he remain in the secular world. Alfonso himself was lazy in his studies, preferring to write poetry and compose songs. He refused to marry on several occasions, probably because he was a homosexual. He also developed the nasty habit of being a drunk, and gambling. Because of all these unsavory rumors, Isabella and Ferdinand finally forced Alfonso to marry Danish Princess Elizabeth. Elizabeth desperately loved her husband, but her husband did not return her affections. After the birth of Enrique, heir to the Dukedom of Girona, the couple finally separated. A few years later, in 1517, it became clear that Alfonso had caught a sexual disease from one of his lovers. This disease would eventually kill him.
[7] Charles VIII marries Margaret of Austria in 1494. She dies giving birth to a stillborn daughter in 1498. Anne of Brittany would marry Richard, Duke of York and Normandy, and the two ruled over a joint Breton-Norman Kingdom. After Margaret died, Maria was sent to marry the widower. Charles and Maria did not love each other, but were at least friendly. Certainly they mist have been somewhat close, for the marriage would result in ten children.
[8] Catalina, the baby of the family, was a sweet and devoutly pious young woman. She would marry Ernest of Austria, the eldest son of Emperor Maximilian I and Elizabeth of York. Ernest had been promised the Holy Roman Empire as an inheritance. This caused some drama, because Philip, Maximilian’s eldest son from a first marriage, and also Duke of Burgundy, believed he should be heir. Ernest and Catherine were happy together during their brief marriage, but he two caught influenza in the spring of 1503, which killed Ernest and made Catalina miscarry their second child. When Philip became Emperor in 1509, he made a frequent point to bully and make fun of Elizabeth of York and Catalina. The two lived at a convent outside Vienna. Anne of York, Holy Roman Empress, was herself miserable, especially after her only child, Charles, died in 1512. Philip would die in 1516, childless. Ernest’s only child, daughter Elisabeth was ineligible to succeed, so Ernest’s younger brother, Fredrick, married to a Polish princess with a load of children, became Emperor. Elizabeth of York would return to court, dying in 1543. Catherine would stay at her convent, becoming a nun, and eventually abbess. She was extremely pious, and took care of the poor and sick in her hospitals. Several miracles, including healing, were attributed to her. She finally died in 1570, at the age of 85, miraculous for that time. In 1595, she was canonized as a Saint.
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Ferdinand was afraid that Karl V would "use" Felipe II's marriage to one of the emperor's daughters to "supplant" Maximilian II as successor. While the electors had elected Ferdinand as Karl's, so long as Karl was emperor, they couldn't elect Maximilian as his father's successor. It's also why Ferdinand nullified his brother's abdication wish that Felipe II be created "vicar of Italy" (traditionally the privilege of the duke of Milan) and instead named the duke of Savoy to that position (and possessing that "title" was what the Savoys used to claim the duchy of Milan - even before they had a right to it after the Valois went extinct - as well as to claim precedence over the grand duke of Tuscany).
Doesn't have to. He died childless because D. Sebastiao, D. Henrique and Katharina of Austria refused him permission to marry. And D. Sebastiao treated his cousin like shit that caused his apparent death by suicide. A POD in the 1520s/1530s can make it that Sebastiao is stillborn or his dad dies before marrying.
Emperor Frederick II married Joanna, Countess of Burgundy and Joanna of England
Frederick II of HRE m. Joanna, Countess of Burgundy(a) Joanna of England(b)
1a. Henry b. 1210 m. Margaret of Austria
1a1a. Beatrice II, Countess of Burgundy b. 1226 m. Premysl Ottokar
1a1b. Henry b.? d. 1242
1a2b. Frederick b.? d. 1245
2a. Beatrice of Swabia b. 1212 m. Eric IV of Denmark
3b. Margaret of Swabia m. Albert II of Meissen
1a. Henry b. 1210 m. Margaret of Austria
1a1a. Beatrice II, Countess of Burgundy b. 1226 m. Premysl Ottokar
1a1b. Henry b.? d. 1242
1a2b. Frederick b.? d. 1245
2a. Beatrice of Swabia b. 1212 m. Eric IV of Denmark
3b. Margaret of Swabia m. Albert II of Meissen
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Germaine de Foix gives birth to Ferdinand heir
This is probably quasi-ASB, but here goes:
Fernando II, King of Aragon (1452-1516) 1m: (as OTL); 2m: 1505 Germaine de Foix (b.1490)
[1] Since the emperor doesn’t control Naples to pincer the pope in Rome, Henry gets his annulment. While he’s not big into a second Spanish bride, Anne Boleyn is dead and the idea of flipping the bird at Catherine of Aragon is too good to resist (not that ASB, Henry actually considered naming OTL Elizabeth “Mary” as a similar screw you. Classy guy). It doesn't hurt that Fernando III absolutely loathes Karl V, who's always treated him as though he's a "disloyal vassal" rather than a king in his own right.
@isabella @VVD0D95 @FalconHonour @Awkwardvulture @The_Most_Happy @HortenseMancini @Diego @Kurt_Steiner @Jan Olbracht
Fernando II, King of Aragon (1452-1516) 1m: (as OTL); 2m: 1505 Germaine de Foix (b.1490)
[1m.] as OTL
[2m.] Juan, Prince of Girona (1509-1512)
[2m.] Leonor (1510-1541) m: 1527[1] Henry VIII, King of England (b.1491)
Henry, Prince of Wales (1528-1535)
Elizabeth (b.1530)
Stillborn Daughter (1533)
Edward, Prince of Wales (b.1534)
Eleanor (b.1537)
Arthur, Duke of York (b.1539)
Margaret (b.1541)
[2m.] Fernando III, King of Aragon & Naples (b.1512) m: 1525 Renée de France (b.1509)
Fernando, Prince of Girona (b.1532)
Juan (1533-1536)
Luis (b.1534)
Pedro (b.1535)
Leonor (b.1537)
Ana (b.1539)
[2m.] Blanca (b.1515) m: 1530 François II, King of France (b.1518)
François, Dauphin de Viennois (b.1538)
Louis (1540-1540)
Claude (b.1541)
Blanche (b.1544)
Louis, Duc d’Anjou (b.1547)
[1] Since the emperor doesn’t control Naples to pincer the pope in Rome, Henry gets his annulment. While he’s not big into a second Spanish bride, Anne Boleyn is dead and the idea of flipping the bird at Catherine of Aragon is too good to resist (not that ASB, Henry actually considered naming OTL Elizabeth “Mary” as a similar screw you. Classy guy). It doesn't hurt that Fernando III absolutely loathes Karl V, who's always treated him as though he's a "disloyal vassal" rather than a king in his own right.
@isabella @VVD0D95 @FalconHonour @Awkwardvulture @The_Most_Happy @HortenseMancini @Diego @Kurt_Steiner @Jan Olbracht
VVD0D95
Banned
How does Cathrine die? And how does henryntreaty Leonor? Also intrigued to know what fernando and Karl’s relationship does for handling frabce
How did Anne die? Why does the pope not get controlled this time around? Why doesn't Fernando III stand up for his aunt the same way Charles V did? Why would it be a screw you to Katherine of Aragon who would probably be quite happy with a second Spanish royal bride (at least compared to French-raised commoner Anne Boleyn)? Why would Charles V treat Fernando as a "disloyal vassal"? It's a very cool scenario - I'm just curious
Also what happens to Ferdinand and Isabella's descendants in this TL with living issue from Germaine @Kellan Sullivan
presumably returned to Castile in disgust (I don't see Henry wanting her hanging around - he's so classy I could even see him kicking Cat out and then giving Leonor the stuff he took from his ex-wife. He did it with Anne and Jane, so I don't see why he wouldn't do it here), Mary stays legitimate under the annulment, so she'd probably make a far better, far earlier match than OTL (presumably to James V). Henry and Leonor are...well, not Anne Boleyn-Henry but not Jane Seymour type submissive either. The fact that she gives him a surviving son right off the bat (albeit he later dies) probably doesn't hurt either.
James VI of Scotland, twin of Mary
James V m. Madeleine of Valois
1. Margaret b. 1537 m. 1552 Edward VI of England b. 1537 d. 1553
- Henry IX b. 1553 m. 1572 Margaret of Valois b. 1553
- miscarriage
- premature stillborn
- Edward VII of England and I of Scotland b. 1575 [1] m. Marie de Medici b. 1575
2. James VI of Scotland b. 1537 m. Margaret of Austria b. 1536
- no surviving issue - [2]
[1] After the birth of the requisite heir, the royal couple would live separately, resulting in no more children.
[2] Margaret had one miscarriage resulting in her infertility. James VI however was still desperately in love with her so he refused to accept an annulment and would accept his nephew as heir.
1. Margaret b. 1537 m. 1552 Edward VI of England b. 1537 d. 1553
- Henry IX b. 1553 m. 1572 Margaret of Valois b. 1553
- miscarriage
- premature stillborn
- Edward VII of England and I of Scotland b. 1575 [1] m. Marie de Medici b. 1575
2. James VI of Scotland b. 1537 m. Margaret of Austria b. 1536
- no surviving issue - [2]
[1] After the birth of the requisite heir, the royal couple would live separately, resulting in no more children.
[2] Margaret had one miscarriage resulting in her infertility. James VI however was still desperately in love with her so he refused to accept an annulment and would accept his nephew as heir.
Do NOT work as both Fernando and Charles would support Catalina‘s place as Queen of England (if anything Fernando would support her while Charles will not do it)
Sweat? Horse-riding accident? Randomly struck by lightning?
Could be anything from a different pope to the fact that Karl doesn't have the same clout as "emperor and king of "part" of Spain" as he did as "emperor and king of Spain and Naples". Maybe Fernando el Catolico gets his favourite grandson in as king of Castile, maybe...
because Fernando has never met his aunt. Never been promised to her daughter. IIRC Germaine didn't have the best relationship with her stepchildren (or the Castilians, for that matter), so it could be the "sins of the fathers" (or the mothers, in this case)
Because Katherine saw it as her "divinely-ordained" future to be queen of England, even if that meant disagreeing with the pope. She wouldn't step aside for anyone, even one of her contemporaries said that if the Archangel Gabriel were to descend from Heaven and tell her to step aside, she'd say "let me talk to the Manager".
Karl likely has the opinion of "I'm older, smarter, richer, and more powerful than you, Fernand, so you have to do as I say. Like marry my sister, okay? Then we're gonna go to war with France because I said so. And you can't get any of my toys that I'm getting from the New World because it's Castilian property. And stay out of my room [Castile] while I'm gone". The list of things that could rankle would be near endless.