Major Literary Sources
- The Troublesome Reign of King John, King of England (1591): Plenty of literary scholars think this anonymous play is Shakespeare's major source for King John.
- Raphael Holinshed's Chronicles of England, Scotland, and Ireland (2nd edition, 1587): Shakespeare's primary source for history plays like King John and also other works like Macbeth.
- Divine Right Theory of Kingship (3.1)
- Corrupt Clergy (3.1)
- The [Spanish] Armada (3.4)
- King John's Submission to Rome (4.3)