There’s indeed a cake called Napoleon, which is not invented by Napoleon. I know at least in Russia and China, this cake is known by the name of Napoleon cake.
Legend has it that the name originates from the Napoleonic war with Russia and since people have to throw the cake to the ground (table?) to break the sugar layer on top of it and thus the Russian people call it Napoleon so that they are breaking Napoleon.
I see no mention of this etymology elsewhere, so take this with a grain of salt.