With a PoD after 5000 BCE, prevent the emergence of the specific Eurasian variety of nomadic steppe-dwelling soceties which are based on horsemanship, i.e. horse-drawn wagons, riding horses, later horseback bowmen etc.
(The PoD limit prevents any very early extinctions of the horse in Eurasia, just to be on the clear side. Later extinctions, if deemed feasible, are in order, though.)