Much of his youth was spent at the English court, after his sister Matilda (1080–1118) married King Henry I of England in 1100. After succeeding his brother Alexander I as king of Scotland, David established a strong administration on the Norman model, bringing many retainers with him from England, encouraging the development of trade, and introducing legal reforms. In 1136, after Henry’s death, David invaded England in support of his niece Matilda’s claim to the throne, but was decisively defeated at the Battle of the Standard in Yorkshire in 1138.