One thing about Eddie Izzard's humorous comedy sets is that he makes history entertaining, and people come away having learned something.
In this case we learn something about Charles I, one of England's bloodiest Kings, who started two civil wars and because of that was beheaded.
Charles I claimed that he was appointed by God to rule and because of that his say was final and he could do whatever he pleased.
One might not think it's possible to build a comedy routine around this nugget of history - one would be wrong.