What is “assize” in medieval legal context (England/Norman sphere)?

The story behind the answer

Assizes were the periodic sittings of royal justices who rode circuit through England’s counties to hear cases, and the term also extended to the binding rules they applied. From Henry II’s reforms in the 12th century, these sessions used standardized writs—such as novel disseisin and mort d’ancestor—to resolve disputes quickly, shifting authority from local lords to royal justice and fostering the rise of jury procedures and the common law.

Some renowned examples are kingdom-wide enactments: the Assize of Clarendon (1166) reorganized criminal investigation via juries of presentment; the Assize of Arms (1181) mandated military equipment for freemen; and the Assize of Bread and Ale set prices and measures. Through these courts and ordinances, “assize” came to signify both the venue of justice and the legal rules shaping medieval English society.