Fergus of Galloway married to David's older sister, Edith (died 1118), a union which closely bound him to the Scottish royal house. For as long as Henry I lived, relations between him and David remained harmonious. When the former died in 1135, however, the peace between the neighbouring realms was shattered when his nephew, Stephen of Blois, Count of Boulogne and Mortain (died 1154), successfully seized the throne. Before the end of the year, the Scots surged forth and seized Carlisle and Cumberland before peace was restored. Relations broke down the following year, and the Scots again invaded in 1137, seizing Northumberland, and
Henry I of England December. The Empress Matilda did not give up her claim to England and Normandy, leading to the prolonged civil war known as the Anarchy between 1135 and 1153. Historians have drawn on a range of sources on Henry, including the accounts of chroniclers; other documentary evidence, including early pipe rolls; and surviving buildings and architecture. The three main chroniclers to describe the events of Henry's life were William of Malmesbury, Orderic Vitalis, and Henry of Huntingdon, but each incorporated extensive social and moral commentary into their accounts and borrowed a range of literary devices and stereotypical events from other popular