That must have been muddled up with the German factor at least since the  rise of Prussia in the Seven Years' War. If my source is right, the Central Europe idea got traction in the West in the form of the German Threat (and in Prussia/Germany Mitteleuropa became popular in the form of natural hegemonic area for regional dominance). Then again, it also claims that the East-West division idea finally supplanted the North-South idea (in which Russia was the Giant of the North) only with the Crimean War.

_{*Lunatic*, n.
One whose delusions are out of fashion.}