The existence of an ancient constitution representing a golden age of English liberty was seen by royalist historians as mythical, and the contemporary historian J. G. A. Popock confirms their view. Developed by Parliamentary lawyers in the 1600s to justify the deposing of the king of England, this ancient constitution distorted English political and legal history. Sir Edward Coke and William Blackstone interpreted English common law to invent this ancient constitution to undercut the authority of the English monarchy and to transfer political power to the republican Parliament. By situating liberal English rights to political participation and property in an ancient constitution that existed before the English monarchy (which justified its sovereignty on past heredity), the Parliamentary lawyers justified overthrowing (or at least limiting) the monarch. The lack of historical validity of this ancient constitution did not prevent others, notably American colonists like Thomas Jefferson, from employing it to justify American independence from the British government in the 1770s, claiming the right to self-government and liberty from the ancient constitution. So this idea, developed by the English Parliament, was eventually used against that same Parliament by the British colonists who learned it studying English law in America.

The reality is that British liberal ideals of natural rights to life, liberty, and property, developed by philosophers such as John Locke, were projected back into history as an ancient constitution to support a political struggle in the 1600s in England and the 1700s in America. It is an example of using (or inventing) the past to affect contemporary politics.