Somewhat related: I remember it being a little disturbing to learn that during this period (and for a long time before) the leaders of the most powerful countries were related.
Tsar Nicholas II of Russia, Kaiser Wilhelm II of Germany, and King George V of the United Kingdom were first cousins. Not to mention leaders of Norway, Denmark, and others.
Considering that, it's almost surprising how stable the time was.
There's a bunch of very interesting, increasingly panicked telegram correspondence between those 3 specifically in the prelude to WWI as they all try to avoid going to war without having a whole lot of choice. I can't find the info about George V, but [0] has more about the telegrams between Nicholas II and Wilhelm II.
Perhaps it's the opposite angle. When they're all family, it's understandable why things were so stable. Any nationalism and cultural differences that might cause tribalistic wars were tempered by family ties and shared blood of the leadership.
Stable...until it went completely bonkers in WW1. The flipside of "stability" is often "unable to change course when something bad happens". The fundamental problem in WW1 is nobody on any side willing to admit this wasn't working for them. In France the and U.K., they could have electoral upheavals. In Russia, Austro-Hungary, Germany, and the Ottoman Empire, they monarchies were all eliminated either during WW1 or immediately after, in large part because they couldn't change course. Stability is only a virtue if you're not screwing up.
> Stable...until it went completely bonkers in WW1
Even WW1 was stable compared to some of the all in brawls that plagued Europe, at least you knew who was on which side for the most part. By comparison look at the Thirty Years War: https://en.wikipedia.org/wiki/Thirty_Years'_War#Involvement
Tsar Nicholas II of Russia, Kaiser Wilhelm II of Germany, and King George V of the United Kingdom were first cousins. Not to mention leaders of Norway, Denmark, and others.
Considering that, it's almost surprising how stable the time was.