Corporal John is a set of free wargames rules for the Age of Marlborough. The author writes that:
The set can be used, not only for Marlborough’s wars, but for those of Charles XII, Peter the Great, Louis XIV and even Gustavus Adolphus.
The rules are fast-play but still retain the detail to give the correct flavour of the period. They will handle games of thirty or forty units per side or much smaller games with a handful of units.