In institutions, Aragon proper must be distinguished, throughout this period, from the Catalonian region of the greater kingdom of Aragon. Social differences were much more marked than in León and Castile, for there was an excessively privileged feudal nobility, which had a despotic power over the servile classes; the movement for emancipation from slavery and serfdom belongs to a much later time. Lords had a right even to kill their serfs. Slavery (confined usually to Moslems) was not personal, for the slaves were attached legally to the land. What has been said for Castile as regards the church, the Jews, Mozárabes, and Mudéjares applies generally for Aragon. There were more Mudéjares than in Castile, but, although they enjoyed equality with Christians before the law, they were on a lower plane socially, and were more heavily taxed. The practice of living in communal family groups was the rule in Aragon. [Sidenote: Political life and administration in Aragon.] The nobles had privileges of a political, as well as of a social character, being virtually sovereigns on their own estates. One noteworthy official to develop was the _Justicia_ (Justice, or Justiciar), charged with hearing cases of violation of privilege and complaints generally against the authorities. The nobles tried to take the appointment of this official to themselves, but failing in this were, nevertheless, able to compel Jaime I to recognize that the functions of the _Justicia_ were to be exercised in his own right, and not by delegation of the king,--for example, in cases in which the _Justicia_ acted as judge, or mediator, between the nobles and the king. The free towns usually sided with the crown, as in Castile, but they were not nearly so numerous, and not equally an agency for the liberation of the servile classes. According to some writers they were represented in the _Cortes_ as early as 1163 (which was earlier than in León), but others make 1274 the date of their entry. There were four estates in the Aragonese _Cortes_,--the higher nobility, the _caballeros_, the clergy, and the representatives of the towns. Aragon and Catalonia continued to have a separate _Cortes_ after the union of the two states, and Valencia also received one of its own, but there were times when a general _Cortes_ of the entire kingdom was held. The principal form of legislation was that of the royal charters. The same diversity of law existed as in Castile, but Jaime I did something to bring about unification by having a code drawn up. This code, called the _Compilación de Canellas_ (Compilation of Canellas), for one Canellas was the compiler, embodied the traditional law of Aragon, supplemented by principles of equity. It did not do away with the charters, applying only to matters which they did not cover. The Roman law of Justinian and the canon law, both of which greatly favored the king, were beginning to be studied, but the nobility opposed the assertion of these legal