Thousands of years before the Romans and the Venerable Bede, Northumberland was a landscape of hilltop forts, many of which can be traced today. Military order was imposed on the region by Hadrian's legionaries, who built the 73-mile northern frontier of the Roman Empire across the county. Through the Dark Ages and into Medieval times, the kingdom of Northumbria was governed from massive castles, and the constant threat of the Border Reivers is evidenced...