The Kingdom of Poland declared on this day, 1916

 Flag of the Kingdom of Poland.

Poland, as a monarchy, was declared to be independent by the Central Powers during World War One on this day.

One of the oddities of history is that it was Germany and Austria that created a Polish state, albeit one of somewhat questionable independence, during the First World War, out of territory that had been part of Polish Imperial Russia.  The Poles themselves were divided in loyalty during the war, including those who favored independence but opposed the Central Powers.  The Poland that would emerge after the war would do so after a tense period of time in which German forces continued to have an influence in the immediate postwar period as the Polish factions worked out their differences.

The Act of November 5, 1916.

Germany and Imperial Austria, in the Act of November 5, promised to create an independent Polish Kingdom out of Congress Poland.  The declaration was not entirely genuine, in the case of Germany, which actually promised to annex some of the territory which it seemed to be promising to a new Polish state.  No Polish government was created following the act and an effort by German authorities to recruit for a Polish army devoid of a government met with protests in Warsaw.

By this point in the war nearly every combatant was promising Poland some sort of independence following the war, and both the Allies and the Central Powers would soon be fielding some sort of Polish forces.