An historical fact that I was not aware of

Samizdata has a fascinating article:

'You never stop learning strange things, do you? For instance... in the year 1612, the heir to the throne, James I's son Prince Henry, rather foolishly went for a swim in the Thames, caught typhoid, and died...

And who became king of England instead? Why, only Charles I, who got himself executed in 1649, in the midst of a ferocious civil war between himself and his severely angered Parliament. That I had heard about. Prince Henry was apparently, and in fascinating contrast to his younger brother, a Protestant:

Henry was quite the Protestant - when his father proposed a French marriage, he answered that he was 'resolved that two religions should not lie in his bed'.

You can't help wondering: What If? What if Prince Henry had not gone for that swim, and had become the King instead of Charles I? How might English history have turned out then?'

What indeed?