I don’t think you could call it reasonably successful. For example, much of European history consisted of war and succession disputes. The entire system of aristocracy was prone to instability and shifting alliances. It turns out hereditary succession is not a good way to choose a competent political leader.
The Politics of Succession, by Andrej Kokkonen, Jørgen Møller, Anders Sundell
https://www.google.com/books/edition/The_Politics_of_Success...
> this book also shows that the development and spread of primogeniture - the eldest-son-taking-the-throne - mitigated the problem of succession in Europe in the period after AD 1000. The predictability and stability that followed from a clear hereditary principle outweighed the problems of incompetent and irrational rulers sometimes inheriting power. The data used in the book demonstrates that primogeniture reduced the risk of depositions and civil war following the inevitable deaths of leaders.
> The predictability and stability that followed from a clear hereditary principle outweighed the problems of incompetent and irrational rulers sometimes inheriting power.
It doesn't though, incompetence is more dangerous than uncertainty. If someone wants to be a hereditary head of state as a formality, then ok that is one thing. But if we look at the most successful nation in the 1000s it is probably the UK, who haven't allowed the monarch to be in the room where the big decisions get made since Charles I was executed in 1649. From that point it is a stretch to say that the monarch is inheriting power. The power to agree cheerfully with what their government tells them to do, perhaps.
The Prime Minister meets the monarch every week. It's very, very naive to assume they only talk about the weather.
The Queen was known to object to legislation that affected her personally. And the monarchy - as the head of the aristocracy, the biggest land-owner, a major influence on the Tory Party, and a private corporation with significant business interests - can always use back-channels and cut-outs to have its say.
The British specialise in this kind of indirect hinting and insinuation. It's part of the culture at most levels, and it drives foreigners insane, because until you learn the subtext you'll completely misread what's being said.
> But if we look at the most successful nation in the 1000s it is probably the UK
There is also a solid argument to be made for France.
>It turns out hereditary succession is not a good way to choose a competent political leader.
It beats strange women lying in ponds distributing swords
Farcical aquatic ceremonies have their uses.
Binding people to a shared worldview due to a fear of an unsuccessful afterlife?
History says: proved useful.
> It turns out hereditary succession is not a good way to choose a competent political leader.
I'm not sure republics have cracked that one either.
I read that at some point the system in Turkey devolved to the point that succession was always determined by a civil war.
This produced a very long string of extremely competent leaders, but the cost was too high.
Let's try technocracy!