Anglo-Saxon society was feudal in nature, and based therefore on reciprocal arrangements between the king and all those lower in the societal order. The principal conflicts of this period, such as the Norse invasions and the Norman Conquest, all relied on troops raised by kings from ealdormen and thegns from whom they had received sworn fealty. As in later medieval times, kings offered land in this era in exchange for military support in times of war, and thus holding regular royal councils was means of ensuring nobles held input and viewpoints into defence needs, and legislative planning and feasibility when demanded. The Chronicles state that various kings of the period, during the Heptarchy and the later united England, consulted their nobles and senior clergy to witness charters and collectively form laws for the common good. This is most noted, perhaps, by the Chronicles concerning Offa of Mercia and Alfred the Great of Wessex respectively, and Æthelstan, Eadred, Edgar the Peaceful, Æthelred the Unready, and Cnut the Great, of the eventual sole Kingdom of the English. The Chronicles in many instances cite numerous Witans that were held for the aforementioned purposes, and by the aforecited monarchs of the period. The purpose of the Witan, therefore, was to ensure that those who were responsible for fighting wars, and implementing laws (more so in the case of ealdormen who held administrative control over countries and major towns/cities), could not only offer input but also forestall any potential rebellion from a lack of inclusion in this process.