I was just wondering as to how solid Spain’s union was during the war of the Spanish Succession? Since AFAIK, it was still a personal union of the crowns of Aragon and Castile (and their constituent kingdoms – Majorca, Valencia, Leon and Asturias etc). Admittedly it would lead to all sorts of incidents, but is it possible to have a split Spain – with Charles of Austria as King of Aragon, and Philippe de France as King of Castile – though how possessions like Naples, Sicily, Sardinia, the Spanish Netherlands, and Milan (as well as the colonies) would be divvied up I have no idea.