Assises de Jérusalem (legal manuscripts)

Also known as Livre de Jean d'Ibelin, Livre au roi, Livre de Philippe de Novare

The surviving 13th-century treatises that record the customary law of the Kingdom of Jerusalem — the practical body of evidence for what the Assizes actually were.

Although tradition held that the kingdom's customary law was first written down by Godfrey of Bouillon and his barons and deposited in the Holy Sepulchre, no such 'Letters of the Holy Sepulchre' have ever been found, and most modern scholars regard the story as a 13th-century legitimating myth. What does survive is a remarkable cluster of legal treatises composed mostly in the second half of the 13th century, mostly in Cyprus, that together preserve a great deal of the kingdom's customary feudal law.

The principal texts are: the Livre au roi (c. 1198–1205), the earliest, an anonymous handbook of the king's rights and duties; Philip of Novara's Livre de forme de plait (c. 1252–58), a working courtroom manual; John of Ibelin's huge Livre des Assises (c. 1265), the most ambitious of all, a baronial constitutionalist's account of the entire system; the shorter Livre of John of Jaffa (c. 1260s); and the bourgeois Livre des Assises de la Cour des Bourgeois.

All these texts post-date Hattin and were written in conditions of political exile or contraction. They are uneven witnesses to the practice of the 12th-century kingdom — they tell us as much about the political values of the 13th-century Cypriot baronage as they do about Godfrey of Bouillon's councils — but together they remain the single richest body of feudal law to survive from anywhere in Latin Christendom.

Read more on Wikipedia: English article