Settlement on the Mendip Hills appears to fall into two types. The first, apparent in the Neolithic and Bronze Age Britain periods, and repeated on a small scale in the Middle Ages and post-medieval era, comprised occupation by self-sufficient groups in small communities or isolated farms. The second was represented in the Iron Age Britain and Roman periods by large sites with specialist functions, existing by virtue of their ability to exert power over lowland producers. From the Iron Age onward the ownership of land took on increasing importance, with large landholdings based on the mines or on stock grazing, denying settlers access to the plateau or forcing them off the hills.