Wace, the 12th-century historian, wrote of the council, convened shortly before the actual invasion, likely in January 1066.
William of Poitiers, a chronicler of the Norman invasion, claims that the duke also obtained the consent of Pope Alexander II for the invasion, along with a papal banner.
[1] William of Poitiers nevertheless describes the council and gives an account of a debate that took place between among the nobles and supporters over whether to risk an invasion of England.
Although some formal meeting probably was held, it is unlikely that there was significant debate, as the duke had by then established control over his nobles, and those assembled would want to secure their share of the rewards from the conquest of England.
Douglas, David C., William the Conqueror: The Norman Impact Upon England, University of California Press, Berkeley, 1964 Freeman, Edward A., The Norman Council and the Assembly of Lillebonne, from The History of the Norman Conquest of England, Cambridge University Press, London, 2011 (archive)