One of the key turning points in English history for myself was the death of Henry Stuart in 1612. Strong, virile, and everything the heir to a throne should be, few suspected that in 1612, Henry Stuart would die of typhoid fever at the young age of 18 years old. It makes you wonder what would have been the fate of the English royal line if Henry had lived. As it was, his brother Charles the I was beheaded in 1649, and the royal line was all but abolished as Oliver Cromwell took over and established the Commonwealth of England. A lot of this could said to have occurred due to Charles' firm belief in his divine right as the ruler of England and that he should not be subject to charges like any average citizen.
So if Henry had lived to become King Henry the IX of England, would have Oliver Cromwell still succeeded in taking down the British Royal Line? What does his survival's effect have on England? Would we today have a Stuart on the throne rather than a Windsor?
Steady the buffs, I think a space of 300 years is pretty difficult to predict which dynasty would be in power.
But let's
assume Henry doesn't die of typhoid. His plan was to accompany sister, Liz, to Germany to go find a good Protestant bride for himself. Assuming the age gap isn't
too large (as in, she's still in single digits age-wise), we'd be looking at a marriage anytime between 1613 and 1615. No henriette Marie in England - which might in and of itself be a good thing. Assuming of course that Harry's bride isn't a Protestant version of HM.
Harry's Protestantism is an interesting thing in and of itself. He seems to have been as stubborn as Charles and his dad, and his Protestantism tending more towards the Low Church end of the spectrum (remember, Charles I was the first monarch to be raised within the fold of the Church of England). Whether that'd be adjusted at a later point, IDK. But there's a good possibility that James I has surviving male line grandkids by the time he dies.
However, Henry was also
not his dad in another way. James wanted to be the arbiter of Christendom - squarely between Protestant and Catholic. Henry would most likely have been for a war against France (in defense of his coreligionists at La Rochelle etc) or Spain (dirty papists). I remember reading an article a while back (can't remember the name, think it was something like
The Militant Prince, the Pacific King) which questioned whether Henry
really was as bellicose as he is often portrayed, or whether it was simply a case of "what my dad is, I'm not" opposition propaganda that would've been turned on its head the minute James was dead.