The Assizes of Jerusalem (Fr. Assises de Jérusalem) are a collection of French legal texts that originated at the courts of the kings of Jerusalem and Cyprus between the end of the twelfth and the second half of the thirteenth century.
The collection consists of a number of different works: the Livres (i.e., law books) of John of Ibelin (Jaffa), Geoffrey Le Tor, James of Ibelin, and Philip of Novara, as well as the Clef desAssises, the Livre au Roi, the Livre du Plédéant, the Livre du Plaidoyer, the Assises de la Cour des Bourgeois, and the Lignages d’Outremer. All of these were originally autonomous works, without any official character, and were only later brought together under the title Assizes of Jerusalem. This title is misleading, according to Maurice Grandclaude, since it implies the creation of a single corpus of laws.
According to tradition, a number of laws (Fr. assises) were recorded on the order of the first ruler of Jerusalem, Godfrey of Bouillon (d. 1100), as claimed by John of Ibelin in his Livre. In fact, the earliest laws were almost certainly compiled under Godfrey’s successors. They were supposed to have been written down on loose leaves of parchment and deposited in the Church of the Holy Sepulchre (whence they derive their name, Letres dou Sepulcre), but they were lost after the battle of Hattin in 1187.
The Assizes of Jerusalem resulted from an attempt by later jurists to fix in writing the memory of these old laws, by bringing together various written records concerning governance. The Assizes are preserved in about thirty more or less complete manuscripts (some of which are of a later date) dispersed in different libraries. These texts were so important that they inspired the compilation of other law codes in Frankish Greece, Antioch, and Cilicia (Lesser Armenia), and were also translated into Italian and Greek.
The Assizes of Jerusalem constitute an important witness to the law of Outremer and a precious source of information on the functioning of institutions in the states of the Latin East.