This would be a mounted skirmisher from ancient Numidia, a Berber-speaking kingdom along the North African coast in what is now Algeria to eastern Tunisia. The Numidians were equestrians of high renown in their part of the world, applying their skills as cavalry alongside both the Carthaginian and Roman armies. And they really did ride their animals bareback as portrayed here!
(Though it appears that I erred in giving the horse reins with bits, as Roman authors mention that the Numidians had no bits and instead used light sticks to direct the horses’ muzzles.)