J.h. Elliott said this quote
“ The kingdom of Aragon possessed an official known as the Justicia, for whom no exact equivalent is to be found in any country of western Europe. An Aragonese noble appointed by the Crown, the Justicia was appointed to see that the laws of the land were not infringed by royal or baronial officials, and that the subject was protected against any exercise of arbitrary power. The office of Justicia by no means worked perfectly, and by the late fifteenth century it was coming to be regarded as virtually hereditary in the family of Lanuza, which had close ties with the Crown; but none the less, the... ”