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
Sussex in the High Middle Ages England was unsuccessful. Following charges against Robert de Bellême around his support for the failed invasion of Robert Curthose, Robert de Bellême fortified Arundel Castle around 1101. This led to forces of Henry I besieging Arundel Castle in 1102 for 3 months, building siege castles in the vicinity of Arundel including probably at Warningcamp and perhaps Ford. Henry I's forces confiscated the castle and held it himself. As the second wife of Henry I Adeliza of Louvain was Queen of England from 1121 until Henry's death in 1135. On their marriage in 1121 Henry gave Adeliza the city of Chichester