Assizes of Jerusalem The Assizes of Jerusalem are a collection of numerous medieval legal treatises containing the law of the crusade r Kingdom of Jerusalem and Kingdom of Cyprus . They were compiled in the thirteenth century , and are the largest collection of surviving medieval laws . History . As Peter Edbury says : " one group of sources from the Latin East that have long excited the attention of scholars are the legal treatise s often known collectively , if somewhat misleadingly , as the Assises of Jerusalem . " ( Peter W . Edbury , " John of Ibelin and the Kingdom of Jerusalem " , pref . ) The assize s , or " assises " in French , survive in written form only from the 13th century , at least a generation after the collapse of the Kingdom of Jerusalem . The earliest laws of the Kingdom were promulgated at the Council of Nablus in 1120 , but these laws seem to have fallen out of use and were replaced by the assizes by the 13th century and presumably even earlier . Although no laws or court cases survive from the height of the kingdom in the 12th century , the kingdom obviously had laws and a well - developed legal structure . By the 13th century , the development of this structure was lost to memory , but jurists such as Philip and John recounted the legends that had grown up about the early kingdom . According to them , both the Haute Cour and the burgess court were established in 1099 by Godfrey of Bouillon , who set himself up as judge of the high court . The laws of both were said to have been written down from the very beginning in 1099 , and were simply lost when Jerusalem was captured by Saladin in 1187 . These laws were kept in a chest in the Church of the Holy Sepulchre , and were thus known in Old French as the " " Letres dou Sepulcre " . " The chest supposedly could have only been opened by the king , the Patriarch of Jerusalem , and the viscount of Jerusalem . Each law , according to Philip , was written on one page , beginning with a large initial illuminated in gold , and with a rubric written in red ink . Philip claimed to have obtained his information from an old knight and jurist named Ralph of Tiberias , and John in turn probably got his information from Philip . Whether or not these legends were true ( Edbury , for one , believes they were not ) , the 13th century jurists envisioned the legal structure of the kingdom to have existed continuously from the original conquest . Texts . The surviving collections of laws are : Also important on its own , although found in the " Livre au Roi " , Philip , and John , is the " Assise sur la ligece " , a law promulgated by Amalric I of Jerusalem in the 1170s , which effectively made every lord in the kingdom a direct vassal of the king and gave equal voting rights to rear - vassals as much as the greater barons . Modern editions . All of these works were edited in the mid - to late - 19th century by Auguste Arthur , comte de Beugnot , and published in the " Recueil des Historiens des Croisades " by the Académie des Inscriptions et Belles - Lettres , in two volumes designated " " Lois " . " Also included in the RHC are the 13th - and 14th - century ordinances of the Kingdom of Cyprus ; a document concerning succession and regency , written by ( or attributed to ) John of Brienne , king of Jerusalem ; and a document concerning military service , written by ( or attributed to ) Hugh III of Cyprus . There are also a number of charters , although a far more complete collection of charters was collected in the late 19th and early 20th century by Reinhold Röhricht . In the judgement of all later editors , from Maurice Grandclaude in the early 20th century to Edbury today , Beugnot was a very poor editor ; fortunately , some , but not all , of these works have been edited separately . A French critical edition of the " Livre au Roi " was published by Myriam Greilshammer in 1995 , and in 2003 Edbury published a critical edition of John of Ibelin ' s text . No new edition of the Old French assizes of the burgess court has been published since Beugnot ' s publication in 1843 , but in the 15th century they were translated into Greek , and from the Greek manuscripts an English translation has recently been made by Nicholas Coureas . Modern historians generally recognize the dangers in attributing 13th - century laws to the 12th - century kingdom , although earlier it was believed that these assizes represented the purest form of medieval European feudalism . In reality the laws probably reflect the practise of neither the 12th or the 13th century , as they were written from scratch in the 13th and were consciously designed to harken back to the less - troubled days of the 12th century , despite the important legal changes that had occurred in the meantime ( trial by ordeal , for example , was outlawed in the Fourth Lateran Council of 1215 ) . As mentioned above , it is somewhat misleading to call all of these texts the " Assizes of Jerusalem " as if they were written together at the same time ; they often contradict one another or omit information that another text has . Together , however , they are the largest collection of laws written in a medieval European state for this period .