Tractatus de legibus et consuetudinibus regni Anglie

Attributed to Ranulf de Glanvill (died 1190) and dated 1187–1189, it was revolutionary in its systematic codification that defined legal process and introduced writs, innovations that have survived to the present day.

Scrutton noted the lack of a heritage owed to Roman law (i.e., the Corpus Juris Civilis) in the Tractatus,[6] stating that some terminology was borrowed solely to be fitted into the book discussing Contracts (Tractatus, Book X), but that the terms were applied to English concepts.

That this is attributable to legal evolution over his reign, rather than to sudden change, is shown by its purposeful inclusion of the principles of his earlier reforms such as the Assize of Clarendon.

Henry II is also noted for choosing strong and very capable men to implement his policies, and then giving them the latitude to do their jobs without interference.

The general unwillingness to grant continuances (essoins) greatly reduced the time needed to complete judicial proceedings.

The King's Court, through its writs, held ultimate jurisdiction in adversarial proceedings over real property.

Establishing the "truth" of facts through the rational process of an Assize Court (later superseded by the jury) was given as an alternative to the options of trial by ordeal, or the use of champions as substitutes, or the use of character testimonials rather than evidence to determine the outcome of legal contests.

More important for the future of England, it was so satisfactory that it contributed to English culture by cultivating a universal respect for law and a willingness to abide by its decision.

Similarly, the judicial oversight of property disputes through the use of writs are the germ for English land law.

The option of the rational process of weighing evidence in a trial by jury would outlive all of its alternatives to become the only way to determine the "truth" of facts.