The opening of the second Impeachment trial of President Trump in the Senate today marks a new stage in the history of a procedure whose origins lie in medieval England.
Queen's consent - to be distinguished from Royal Assent - is one of the most obscure little pieces of parliamentary flummery. Its origin has been traced back to 1729: but it must be older than that.
These days, the parliamentary privilege of free speech is regarded as deriving from the assertion in Article IX of the 1689 Bill of Rights that ‘Freedom of Speech and Debates or Proceedings in Parliament ought not to be impeached or questioned in any Court or Place out of Parliament’. That it is considerably older than that is certain, but how old, very much not so.