A Burh's an Anglo-Saxon name for a fortified town or other defended site, such as a hill fort. The boundaries of ancient burhs can often still be traced to modern urban borough limits. A 10th century document called the Burghal Hidage cites 30 burhs in Wessex, and 3 in Mercia (then under the domination of the West Saxon kings), built to defend the region against Viking raids. Most of these were founded by Alfred the Great, some based on pre-existing Roman structures, some newly built, though som… (More on Burh)