Books of authority

Books of authority is a term used by legal writers to refer to a number of early legal textbooks that are excepted from the rule that textbooks (and all books other than statute or law report) are not treated as authorities by the courts of England and Wales and other common law jurisdictions.

These books are treated by the courts as authoritative statements of the law as it was at the time at which they were written, on the authority of their authors alone. Consequently, they are treated as authoritative statements of the law as it is at the present time, unless it is shown that the law has changed, and may be cited and relied on in court as such.

The statements made in these books are presumed to be evidence of judicial decisions which are no longer extant. The primary reason for this practice is the difficulty associated with ascertaining the law of the medieval and early modern periods.

On the subject of this practice, William Blackstone said:

Abridgements of the year books[edit]





  • The author of the Abridgement of the Book of Assizes (c.1510) is unknown. This book is sometimes called Liber Assisarum, after the Year Book from which some of its cases are abridged.

Treatises, commentaries and institutes[edit]

On the common law[edit]



  • De Legibus et Consuetudinibus Angliae (On the Laws and Customs of England) (c.1250) by Henry de Bracton.[2]




Traditionally, Ralph de Hengham was believed to be a prolific author of common law procedural treatises, and numerous works were attributed to him. These included not only the eponymous Hengham parva and Hengham magna,[3] but also "Cum sit necessarium", "Exceptiones ad Cassandum Brevia", "Fet Asaver", "Judicium Essoniorum", and "Modus Componendi Brevia", among others.[4] More recent scholarly analysis, however, reveals that only the Parva (a set of lectures directed towards junior-level law students) is conclusively his.[5][6] Hengham may also have written two consultations.[7]









On equity[edit]

On canon law[edit]

On the law merchant[edit]


  1. ^ William Blackstone, Commentaries on the Laws of England, Book I, pp. 72 - 73
  2. ^ "De Legibus" was never completed.
  3. ^ Winfield, Percy H. (1925). The Chief Sources of English Legal History. Harvard University Press. Reprinted in 2000 by Beard Books. p. 274. Accessed 16 Feb. 2011. [1]
  4. ^ See, for instance, Woodbine, George E. (1910). "Four Thirteenth-Century Law Tracts". Diss. Yale University, 1910. New Haven: Yale University Press. [2]
  5. ^ Arkenberg, Jerome S. (2002). Hengham, Ralph de (d. 1311). Historical Dictionary of Late Medieval England, 1272-1485. Ed. Ronald H. Fritze, & William Baxter Robison. Greenwood Publishing Group. 244-246. [3].
  6. ^ Brand, Paul. (1993). Nothing which is New or Unique? A Reappraisal of "Judicium Essoniorum"." In The Life of the Law: Proceedings of the Tenth British Legal History Conference, Oxford, 1991. Vol. 1991. Peter Birks, ed. London: Hambledon Press. 1–8. p.6. Accessed 16 Feb. 2011. [4]
  7. ^ Brand, Paul. (1979). Quo Waranto. Law in the Reign of Edward I: A Hitherto Undiscovered Opinion of Chief Justice Hengham. "Irish Jurist" new ser., 14. 124-172.

External links[edit]