"Burggraaf"

I suppose standing on the top of the keep, you could hold guard over the rivers Gulp, Geul and Eyserbeek. It is no large hill, but still there must have been a wooden castle in the 6th century. I often wonder how wide and ferocious the rivers were in that era, because the valley is wide. But nowadays the three rivers are narrow and they flow friendly.
Most of the time.