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 in the masonry of fortified farmhouses, pele towers and churches. There are 600 recognised pele towers in England, stretching as far south as Norfolk and Cornwall; 258 of the 600 are in Northumberland. At the end of the border warfare, the magnificent castles became either romantic ruins or stately homes, while Britain's east coast needed more modern defences against new, foreign enemies. With a fascinating array of images, Colin Alexander tells the defensive story of England's border county, Northumberland, from prehistory to modern times.