Legal history: England & common law tradition: Trial and Execution of Charles I

For the first time, a ruling monarch was the defendant in formal legal proceedings in a High Court of Justice, set up by the act of a Parliament which felt able to profess to be the supreme power in the land. (For text of this act see Rushworth, Historical Collections v 8, 1379)

The charges were that  he "had a wicked design totally to subvert the ancient and fundamental laws and liberties of this nation", and that he had "levied and maintained a civil war in the land."

Charles I denied the competence of the court, and refused to plead.

After four days, this stance was deemed to be a confession. He was sentenced to death, by beheading.