October 31st 1517, Archbishopric of Wittenberg
The Detached Priest Martin Luther converts to the Protestant heresy.
November 7th 1517, Archbishopric of Wittenberg
The Court Chaplain of Saxony randomly passes through the region, Martin Luther converts back the Catholicism
July 1914
KuK Minister: My Emperor, your son Franz Ferdinand has been assassinated during his visit in Sarajevo. We suspect Serbian nationalists behind this.
Franz Jospeh: That's ... excellent! It's an perfect excuse to establish a new satellite in Serbia.
KuK Minister: What?
FJ: You know, a state that does exactly what we order it to do.
KuK Minister: So, new territory for our Empire?
FJ: No, that might totally upset everyone, even the Germans. You know, just a puppet?
KuK Minister: My liege, this is not possible?
FJ: Excuse me?
KuK Minister: You can only claim the Kingdom for yourself or push someone else's claim on the Kingdom. However, the relationship bonus for pushing the claim will only last until the ruler dies. Sadly nobody in your (extensive) dynasty has a strong claim on Serbia, so you won't even get the +5 relationship bonus for the same dynasty and the possibility of the two titles sooner or later falling under the same person. Furthermore, as the country is not in a regency or ruled by a woman you cannot push weak claims. Lastly, no claimant to the throne is willing to join your court.
FJ: ... damn. So we ... just go for good old conquest?
KuK Minister: Very well, do you have a casus belli?
FJ: Those damned Serbs just murdered my son and heir?
KuK Minister: You don't possess a claim on the Kingdom of Serbia?
FJ: No ...
KuK Minister: Then we sadly can not go to war. You could however start to fabricate a claim on their lands.
FJ: How long would that take?
KuK Minister: A few decades, most likely.
FJ: Ok, so we start now andd dear Charles will put those Serbs down to size.
KuK Minister: No no no, my liege, any claim you fabricate will expire the day you die. As you are pretty old already, using your chancellor this way would be highly wasteful. Just send him to improve some relations somewhere.
FJ: So you are telling my that I can NOT declare war on the country that just murdered my son and heir in order to push their claims on Bosnia?!
KuK Minister: Indeed, my lord.
--- two months later ---
FJ: HA! I managed to get all the claims I need within a month! Declare war!
KuK Minister: Our armies are already marching towars Belgrade.
FJ: Very well! How are the Germans and the Turks doing?
KuK Minister: Well, the Germans have refused to join or war, seeing us a "heretics" and also claiming to have higher opinion of Tsar Alexander than to you. The Turks just view us a vile heathens and have declared a Jihad for Hungary as we are now standing alone against the Russians. We are outnumbered 4-to-1.
FJ: *sigh*