Upon the Roman withdrawal from Britain to protect the Roman Empire on the continent in the 5th century, the area of Sutton Coldfield, still undeveloped, passed into the Anglo Saxon kingdom of Mercia. It is during this period that it is believed Sutton Coldfield may have originated as a hamlet, as a hunting lodge was built at Maney Hill for the purpose of the Mercian leaders. The outline of the deer park that it served is still visible within Sutton Park, with the ditch and bank boundary forming the western boundary of Holly Hurst, then crossing Keepers Valley, through the Lower Nuthurst and continuing on south of Blackroot Pool. Due to the marshy ground at Blackroot Valley, a fence was probably constructed to contain the deer, and the ditch and bank boundary commence again on the eastern side, on towards Holly Knoll.