 In 1138, he rebelled against Stephen, starting the descent into civil war in England.Robert renounced his fealty to the King and declared his support for Matilda, which triggered a major regional rebellion in Kent and across the south-west of England, although he himself remained in Normandy.Matilda had not been particularly active in asserting her claims to the throne since 1135 and in many ways it was Robert who took the initiative in declaring war in 1138.