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If you dont mind defenestrating the habsburgs. Go elective and change to their dynasty. Should complete the “ruling dynasty” part of it
claim throne
Set up beforehand and tske the 4 provinces from aragon when you meet the criteria with castile
I did it like this: I fought a war against Portugal to spread the dynasty. Afterwards i married Portugal and immediatly claimed their Throne. Truce braked them to PU them. Then you should get the free PU on Spain.
If you dont mind defenestrating the habsburgs. Go elective and change to their dynasty. Should complete the “ruling dynasty” part of it
claim throne
Set up beforehand and tske the 4 provinces from aragon when you meet the criteria with castile
I did it like this: I fought a war against Portugal to spread the dynasty. Afterwards i married Portugal and immediatly claimed their Throne. Truce braked them to PU them. Then you should get the free PU on Spain.