This year (in fact yesterday, 6th November!) marks the 400th anniversary of the death of Henry Stuart, Prince of Wales (1594-1612), eldest son of James I and elder brother of Charles I. The National Portrait Gallery is currently hosting an excellent exhibition about him, entitled 'The Lost Prince'. Henry was hugely popular: handsome, charismatic, athletic, cultured, martial, a patron of the arts and sciences, everything you could hope for in an heir to the throne. His brother, Charles, idolised him. The future looked bright. Tragically, at the age of 18 Henry contracted what is now thought to have been typhoid fever and, despite the attentions of a team of six doctors and their increasingly desperate treatments, he died. The public reaction must have been reminiscent of that to Diana's death: an outpouring of national grief on an unprecedented scale, at times bordering on hysteria; vast quantities of music, literature and sermonising - both official and private - eulogising the dead Prince appeared. The funeral itself was on a massive scale; the official mourners alone numbered 2000.

Today, however, he is almost forgotten. His collection of thousands of books, works of art, scientific instruments, arms and armour etc was broken up and scattered to the four winds; the location of only a fraction of it is now known. His name survives in such locations at Cape Henry in North America, but few probably know who they're named after. Indeed, the vast majority of people have probably never heard of him.

And of course there is the other issue... if Henry hadn't died, he would have eventually become King Henry IX, and there would have been no Charles I. Who knows how that could have turned out? He was quite a different character from Charles; devoutly Protestant, with none of the High Church leanings that would prove so damaging to his brother; well versed from childhood in the statecraft that had allowed his father James to successfully negotiate the volatile politics of 17th century England. It seems likely the Civil Wars would never have happened - at least, not at that point! - and England's history would have swung in a very different direction. An intriguing prospect.

It has always seemed to me that from the point of view of democracy and constitutional monarchy and the rise of Parliament England was lucky to have an early revolution which was an interruption more than a complete change. If divine rights etc had still been the style in the late 18th century then England might have gone the way of France or Russia with an excess of violence and a complete upheaval.

The description of Prince Henry, though, isn't too far away from how Henry VIII was described in his youth, is it? Sometimes your reputation is better left as it was when you were young, though of course, at least everyone has heard of Henry VIII. (By 'everyone' I don't of course mean the whole population of Mali or Laos, perhaps.) I doubt if he would have been known as Henry IX, anyway. Once a king has blotted his copybook and surely for the Stuarts Henry VIII had, their name doesn't seem to be used any more. Not a lot of Johns, and no more James. In fact we seem to be stuck with George for the duration now. William, I suppose, is quite satisfactory.

Why are there no Thomas kings? Every second man of note in Reformation times seems to be Thomas - Cromwell, Cranmer, More, Seymour, A'Becket a little earlier. But no King Thomas.

Prince Henry Frederick was very approving of his sister Princess Elizabeth's proposed match to the Protestant Frederick, Elector Palatine.

I don't think it would've made much of a difference. The concept of primogeniture is by its very nature not meritocratic. So even if Henry IX proved to be an able ruler, chances are that his in-bred son would not, and the Civil Wars would occur...it was just a matter of time.