It has to be Austria and Hungary - by then they were two separate countries. The other three were Allies and along with britain they occupied Germany in 1945.
Considering the countries that stood on the side of England against Hitler, who entered the political scene and headed the German leadership between the two world wars, the only country that could not do it is Austria Hungary. This empire as a defeated party ceased to exist in 1918 after the end of the First World War, when it was divided in Austria and Hungary.
I mean... Eventually some kings left the Papal authority. However, remember the crusades? It united nearly everyone in Europe. Some to the point of making new states.
