When the Prussian Government suddenly declared war on the Kingdom of Denmark, the most bewildered person was King Christian IX of Denmark. He had no idea what was going on when war broke out.
Christian IX had only ascended the throne in 1863. Not long after taking power, he amended the constitution and incorporated the two duchies of Schleswig and Holstein into the Kingdom of Denmark. That was the cause of the Second Prusso-Danish War in history.
In this timeline, Christian IX did the same. Naturally, it provoked the anger of the people in the German region, and the three German states issued warnings.
However, because the Paris Conference provided them with legal justification, and these territories did not border Austria, the Vienna Government merely roared a few times before letting the matter go.
With Austria declining to take the lead, and with Russian support, the Kingdom of Denmark successfully annexed the two duchies.
The facts proved that this bargain was not so easy to seize. The Prussians had endured it at the time, but they had actually been holding back a trump card. Now that the Russians were too busy to look after themselves, they struck.
War was declared on the afternoon of October 24. The Berlin Government did not begin nationwide mobilization until October 25, and on October 27, Prussian troops crossed the border and stormed into Danish territory.
On the surface, this fully complied with international law. Military mobilization had only begun the day after the declaration of war, making it seem more like a decision made on the spur of the moment.
However, not every country was Prussia, with so many troops at its disposal. The Kingdom of Denmark had not exhausted its people and drained its coffers for war; its standing army numbered only a