Attempted assassination of King Ferdinand the Catholic
What would have happened next had Joan de Canyamars's assassination attempt on King Ferdinand the Catholic on the steps of the Barcelona Royal Palace in Catalonia had succeeded?
Especially how would this event affect his wife Queen Isabella I of Castile?
Assume that as an additional POD, Prince Afonso of Portugal survives his 13 July 1491 horse-riding on the Tagus River banks, or alternatively, it never happens at all, butterflying away the death of Isabella of Aragon as well as Prince Miguel da Paz.
Juan, Prince of Asturias, may or may not survive in this TL, depending on the butterfly effects that this POD has. Another interesting possibility in this TL is to have Archduchess Margaret of Austria drown during her voyage to Spain off the French coastline.
And finally, what would the older Isabella likely do to de Canyamars once he is captured? The method of execution will almost certainly not be nice AT ALL, that's for sure.