Meanwhile, civil war had broken out in England between King Stephen and the Empress Matilda, resulting in a period of chaos known as the Anarchy. Matilda's uncle, David I of Scotland, invaded England during 1137 in support of her claim. Although Miles de Beauchamp declared himself in support of Stephen, the king decided to retake Bedford Castle before marching north. Stephen formed an army to besiege Bedford Castle but Miles gained advance warning of the attack and took in considerable supplies, preparing for a long siege. Stephen was unable to storm the castle and left a force under the command of Hugh to starve it into submission whilst he marched north to tackle the Scots invasion.