When was the first dirt bike made and by what company?

Most of the first motorcycles made were basically bicycles with an internal combustion engine strapped on somehow. These bikes were constructed just as "roads" were beginning to appear, so they were built to ride off road as well. Therefore, even the first motorcycles could be referred to as "dirt bikes". So dirt bikes (and street bikes) have been around since the dawn of motorycling, just at the time they were simply considered regular motorcycles.