I realize this question has been posed before, but it didn't really go anywhere, so I'm gonna ask it again.
What might have happened with Crown Prince Hans of Denmark (b. 1518) (brother to the more famous Duchess of Milan) if he had lived? He was the son of a Catholic father and a mother who reportedly was attracted to the Reformation (the Hapsburgs deny this and claim she died a convinced Catholic). His one sister married a Catholic (Christine, Duchess of Milan and Lorraine) while another married a Protestant (Dorothea, Electress Palatine).
Unfortunately he died young, but what sort of man might he have grown into, who and where would he have married (Catholic or Protestant)? Would he have ever gone on to reconquer Denmark et al if he'd had the right backing? Or is he destined to remain maybe an Imperial or Spanish governor of a province - like the Netherlands - and slip into history as a shadowy figure few remember; or maybe be the centre of a sort of Jacobite/Bourbon court in exile?