How long was Anglo-Norman used as a literary language in England?

Anglo-Norman was used as a literary language in England for approximately three centuries. Its history as a literary medium began in the early 12th century during the reign of Henry I, with the latest extant literary texts dating to the early 15th century during the reign of Henry IV.1

Throughout the 12th, 13th, and 14th centuries, Anglo-Norman served as a primary literary language in England, second only to Latin. While the Norman Conquest established it as the vernacular of the court, law, and administration, the increasing alienation toward France during the Hundred Years’ War eventually led to a greater reliance on the English language. Although its use as a literary language declined by the 15th century, the dialect persisted in specific legal and parliamentary formulas, where traces of it survive to this day.12