Kings have taken counsel from their subjects in formal, public assemblies for almost as long as monarchies have existed. Consultation not only flatters those who are consulted and commits them to the outcome. It also reinforces the power of the king in the eyes of others by spreading responsibility for his decisions among a larger group. In this way it mitigates the instability which is inherent in all autocracy. The implicit limitation on the autonomy of the monarch has generally been regarded, even by monarchs, as a price worth paying. As Aristotle was the first to point out, ‘royalty is preserved by the limitation of its powers’.

Until a generation ago, constitutional history dominated the serious study of the English Middle Ages. William Stubbs’s The Constitutional History of England set the agenda for more than a century after its first appearance in the 1870s. And, within the domain of constitutional history, the origin and development