A more thorough explanation:

Definition: Diversité des courts is a French treatise on courts that was supposedly written by Fitzherbert during the reign of Edward III. It was first printed in 1525 and again in 1534. The book provides a list of the matters of conscience that were then cognizable by subpoena in chancery.

Example: "For in the ancient treatise, entitled diversité de courtes... we have a catalogue of the matters of conscience then cognizable by subpoena in chancery, which fall within a very narrow compass." (3 William Blackstone, Commentaries on the Laws of England 53 (1768))

This example shows how the Diversité des courts was used as a reference for the matters of conscience that were handled by the chancery court during the reign of Edward III. The book provided a comprehensive list of these matters, which was useful for legal practitioners at the time.