FoR the Jewish communities of the Crown of Aragon, the almost exclusive predominance of Jewish law or halakhah as the basis of their judicial system was a matter of principle shared with Jews all over the world. The king's recognition of Jewish law as the foundation of the system enhanced its validity significantly. The privileges granted to Jewish communities authorizing them to adjudicate between Jews according to their laws were followed by the equally important royal support of the verdicts rendered secundum legem iudeorum.

Records from the second half of the thirteenth century state clearly that disputes between Jews should be settled according to Jewish law. The fact that Jewish law or halakhah is referred to as açuna, the word in Arabic for law, in documents from 1264 and 1270 concerning the Jews of Saragossa and Lerida respectively leaves no doubt that this was merely a confirmation of a situation dating back to periods preceding the early Reconquista. The use of an Arabic term for Torah or halakhah in aljamas that had been under Christian rule for almost a century and a half since their conquest from the Muslims indicates that there was no interruption in the tradition. The term was used throughout the period to denote Jewish law, and in most sources it appears in connection with the king's policy advocating its use in litigation among Jews. This policy was clear and explicit. All trials between Jews in all Jewish communities had to be conducted according to Jewish law. The charter of Pedro III granting the Jews of Catalonia the right to adjudicate between their members according to Jewish law even in civil and criminal lawsuits, as long as the baile was informed, was confirmed by Jaime II.

In matrimonial cases, the principle was that the settlement should be in accordance with the halakhah, and the Aragonese monarchs were consistent in their support of Jewish matrimonial law. The divorce procedure and women's rights as prescribed by their ketubah, and many other details connected with marriage and divorce, came within the strict boundaries of the halakhah. Refusal by a husband to give a get (divorce bill) to his wife could create an impasse which was difficult to overcome in certain cases unless the king ensured that the obstinate husband appeared before a properly constituted beth din.