William Blackstone's The Great Charter and Charter of the Forest contains the texts of fourteen medieval documents; tracing the history of Magna Carta from the Articles of the Barons in 1215 to the confirmation of the charter by King Edward I (r. 1272-1307) in 1300. The Great Charter was a pioneering piece of historical scholarship; based on examination of the original documents. Most importantly; Blackstone was the first to publish an accurate version of the text of Magna Carta as issued by King John in 1215. In so doing; he was able to establish that the 1215 Magna Carta was significantly different from the version entered on the Statute Roll in 1297 (itself derived from the 1225 Magna Carta)