In military technology, as in nature, for every action, i.e. a new development, there follows a reaction, a counter-measure against the new technology. Exactly this happened in the German Army concerning anti aircraft defence. Beginning with the German French war of 1870/71. the armies used balloons as artillery reconnaissance to locate targets for shelling the hostile front area. As a defence to this reconnaissance the German Army, ruled by an Emperor this time, developed a so-called "Ballonabwehrkanone" (balloon-defence-weapon), abbreviated "ВАК". They were made mobile by being constructed on horse-drawn platform and as such were an early self-propelled weapon. Those rudimentary self-propelled wagons were of course very slow and only of limited use, generally near roads...