When Charles I was captured at the end of the English Civil War, there was some debate amongst the Parliamentarian leaders over what they should do next. One idea was that Charles I should be deposed and replaced with his youngest son, Henry Duke of Gloucester (the other two sons had both fled to France by this point). Obviously this idea came to nothing and Parliament instead opted to execute Charles and set up a republic, but what if they had decided to make Henry king instead?
Bonus question: What if, instead of choosing either of the above options, they decide to take a more "moderate" course of action ("moderate" in that it involves less disturbance to the established rules of succession), and, whilst still deposing Charles I, write to Prince Charles in France offering him the throne? Would Prince Charles accept the offer (possibly because he thinks he'd better be able to keep his father safe from vengeful Parliamentarians)? And with his son on the throne, would Charles I be willing to retire gracefully instead of constantly scheming to get back in power?