Which Norman council approved William's planned expedition to England?

The Norman council that approved William’s planned expedition to England was the Council of Lillebonne.

The council was an assembly of Normandy’s nobles and clergy, held at Lillebonne before William, Duke of Normandy, launched his invasion in 1066. Its purpose was to secure support for an extraordinarily risky enterprise: transporting an army across the Channel to contest the English crown claimed by Harold Godwinson.

Accounts associated with William of Poitiers describe discussion among William’s supporters, while the later chronicler Wace places the council shortly before the invasion, probably in January 1066. Modern historians caution that the scene may have been more formal than dramatic; William had already built substantial control over his leading nobles, who also had powerful incentives to support a conquest.

The council is sometimes confused with papal approval. William’s representatives also sought the support of Pope Alexander II, who reportedly sent a papal banner. That endorsement was politically useful, but it was not the Norman council itself. Lillebonne refers specifically to the meeting of Norman leaders that backed William’s invasion plans.