Definition
The Assizes de Jerusalem were a body of feudal law established by an assembly of crusader barons and lords following the conquest of Jerusalem in 1099. The code governed the Latin Kingdom of Jerusalem and the feudal territories created by the First Crusade in the Levant. Drawing primarily from the customs and laws of France, the Assizes regulated land tenure, lordship, military obligation, and the administration of justice within the crusader states.
The code was not immediately reduced to written form. The original compilations are generally believed to have been lost when Saladin retook Jerusalem in 1187. What survives derives largely from later recensions, most notably the systematic legal treatise composed by Jean d'Ibelin, Count of Jaffa and Ascalon, around 1290 — nearly two centuries after the conquest the Assizes nominally commemorate. Jean d'Ibelin's work is the principal source through which the substance of crusader feudal law is known to modern legal historians.
Why It Matters in Research
This term appears in historical legal dictionaries primarily as a reference point for feudal jurisprudence rather than as operative law. Researchers encountering it in historical sources should be alert to several issues.
First, the 1099 date attached to the Assizes in nearly all historical legal dictionaries is misleading as a date of codification. The assembly of 1099 may have established customary arrangements, but the systematic legal compilations researchers actually consult — the Haute Cour and Cour des Bourgeois texts — belong to the thirteenth century. Treating 1099 as the date of the code conflates the political event (the conquest) with the much later legal literature it inspired.
Second, the Assizes de Jerusalem are significant to comparative legal history because they represent feudal law developed in isolation from the English common law tradition and the Roman law revival occurring simultaneously in continental Europe. They are a useful corpus for understanding how French feudal custom transplanted to a non-European context evolved its own procedural and substantive character.
Third, Law Mind researchers working in feudal land law, medieval legal history, or the history of the assizes as a procedural device more broadly should note that "assizes" here carries its older meaning — a sitting or session of a legislative or judicial assembly — distinct from the English assize of novel disseisin or the circuit court assizes. Cross-referencing with entries on ASSIZE and FEUDAL LAW will help maintain that distinction.
Finally, the Assizes de Jerusalem are occasionally cited in nineteenth-century treatises on feudal tenure to illustrate the universality of feudal principles across Christendom. Researchers should evaluate such citations critically; authors like Blackstone's successors and the compilers of early American digests sometimes used the Assizes rhetorically to suggest a coherent pan-European feudal system that the historical record does not fully support.
Historical Dictionary Support
The four source dictionaries are in close agreement on the basic definition, and in that agreement lies a shared limitation. Black's (both editions) and Rapalje & Lawrence offer nearly identical one-sentence entries: an assembly of barons and lords prepared a feudal code in 1099 after the conquest of Jerusalem. They add nothing about the transmission, survival, or later compilation of the texts.
Bouvier's is the most substantive entry, adding that the Assizes were compiled principally from the laws and customs of France and noting Jean d'Ibelin's later reduction to formal written form around 1290. Bouvier's also provides references — Fournel's Histoire des Avocats, Dupin's Profession des Avocats, and Stephen's Pleading — that suggest the Assizes were of interest to nineteenth-century legal scholars as part of the broader history of legal institutions rather than as living law.
None of the historical dictionaries address the loss of the original texts after 1187, the distinction between the Haute Cour (governing the nobility) and the Cour des Bourgeois (governing non-noble free persons), or the scholarly debate over how accurately the surviving thirteenth-century treatises reflect the original customary arrangements. Researchers requiring that depth should move beyond the dictionary literature to legal-historical scholarship on the Latin Kingdom of Jerusalem.
Jurisdictional Note
The Assizes de Jerusalem never had application outside the crusader states of the Levant and have no operative force in any modern jurisdiction. Their relevance today is purely historical and comparative.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Feudal Law; Assize (Historical); Medieval Legal Institutions