A number of structures have been built on or around the summit of Rubers Law. The earliest may have been an Early Iron Age hill fort or oppidum, represented by the remains of an outer wall, running at the same level around the hilltop, enclosing an area of with a well-marked entrance to the south. No Roman masonry has been incorporated into this wall, suggesting an early date, though it is also possible that it could be the wall of a cattle compound associated with a later post-Roman fort.