Okay, this is an exercise in alternate history building. Here’s the premise: Two sisters’ deaths, in October four years apart, lead to a massive change in European alignments and rule. First, in Lier, now in Belgium, on October 20, 1496, Philip von Habsburg, “the Handsome,” Duke of Burgundy and Count of Flanders is being wed to Juana, daughter and heiress of Ferdinand and Isabella, when from the crowd spring two nationalists, Matthias van Antwerpen and Guilliame de Dijon – whose goal is to prevent the fall of their beloved Burgundy/Flanders into the ambit of Spanish and Austrian rule, by killing the young Habsburg duke who inherited the Duchy from his mother, the last of the Burgundian royal house, and his bride, heiress of Spain. While Philip survives, Juana is killed.
Four years later, on Halloween 1500, the earthquake that in real history destroyed Lisbon in 1555 happens 55 years earlier. Maria de Castile y Aragon, who had the previous day married Manoel, King of Portugal. is among those killed.
The heiress to Aragon and Castile is now the 15-year-old Infante Catarina de Trastamara y Trastamara, de Aragon y Castilla, married by proxy in May of the previous year to Arthur, heir of Henry VII of England.
Everything else stays the same – Henry is even more anxious to make this matrimonial alliance, and Ferdinand and Isabella see England as a good next conquest after Navarre and Portugal, so they confirm the marriage. Catarina sails to England in November 1501, meets Arthur and renews their vows with him in person in St. Paul’s. The young couple come down with the ‘sweating sickness’ and Arthur dies of it. Henry proposes to marry her to his surviving son, the future Henry VIII, and that marriage is agreed on, with papal dispensation.
Now what happens? There’s no Charles V in the picture – his mother died, as did his father later. Catherine is Queen of Castile in her own right after her mother’s death, though her father survives in Aragon. Her husband inherits the throne of England in 1509. Henry is NOT going to want an annulment in this scenario – he’s effectively King of Spain in right of his wife. And the Habsburg marriage alliance route to power is in shambles.
Write the next steps.