To say that the world was on the verge of being lit aflame after the assassination of the Austrian Archduke Franz Ferdinand and his wife was no exaggeration. In Bruno's previous life, the Habsburg Dynasty sent a list of demands to the Kingdom of Serbia, including the matter of an international investigation into the murder of their heir apparent.
There was a common misconception that Serbia had agreed to all of these demands except for one, which was the one that would give up their sovereignty as a nation, choosing instead to fight to remain an independent kingdom.
The reality was that the ultimatum, which "put Serbian sovereignty into question," was the demand that Austria be allowed to conduct a bilateral and international investigation into the assassination of their heir.