The Five Knights' case, also called Darnel's or Darnell's case, 3 How. St. Tr. 1 (K.B. 1627), was an important case in English law, fought by five knights (among them Thomas Darnell) in 1627 against forced loans placed on them by King Charles I in a common law court. Thomas Darnell, John Corbet, Walter Earle, John Heveningham, and Edmund Hampden petitioned King's Bench for a writ of habeas corpus to be set free. The attorney general replied that they were being held "by the special command of his majesty." The question before the court was whether this was an adequate return on the writ. The court found in favour of the King, since common law had no control over the royal or absolute prerogatives of the monarch. The Petition of Right of 1628 clarified this situation and limited the monarch's absolute prerogatives.
John Selden acted as counsel for one of the defendants, Edmund Hampden, in this case; he was a Member of Parliament and claimed afterwards that there was an effort made by the King and Robert Heath, the Attorney General, to tamper with the rulings of the case. While historians have generally agreed with Selden's assertions, Mark Kishlansky has disputed them.
According to some sources taxation, if not sanctioned by Parliament, was declared illegal by this case. On the other hand, Glenn Burgess writes "The Five Knights' Case ... was not about non-parliamentary taxation".