John F. Danby in "Shakespeare’s Doctrine of Nature" (1949) examines the response of Shakespeare's history plays (in the widest sense) to the vexed question: 'When is it right to rebel?’, and concludes that Shakespeare's thought ran through three stages: (1) In the Wars of the Roses plays, "Henry VI" to "Richard III", Shakespeare shows a new thrustful godlessness attacking the pious medieval structure represented by Henry VI. He implies that rebellion against a legitimate and pious king is wrong, and that only a monster such as Richard of Gloucester would have attempted it. (2) In "King John" and the "Richard II" to "Henry V" cycle, Shakespeare comes to terms with the Machiavellianism of the times as he saw them under Elizabeth. In these plays he adopts the official Tudor ideology, by which rebellion, even against a wrongful usurper, is never justifiable. (3) From "Julius Caesar" onwards, Shakespeare justifies tyrannicide, but in order to do so moves away from English history to the camouflage of Roman, Danish, Scottish or Ancient British history.