I saw a map of the troop placements at the start of a pre-napoleonic battle and the map used four x's to represent each army and then three x's for each corps etc. I also wondered how spatially widespread this system was, for example was it just European/western countries that used it pre-ww2?
The first Army to implement the organization of Divisions was the French Army in the mid-1700s, and the Napoleonic Wars saw them be the first to implement Corps and Army level commands. Army Groups did not really appear until WWI, while Brigades, Regiments, Battalions, Squadrons, etc have been used since at least the 1600s.