ASSESSOR. - He is the person who advises and assists the judge in the examination and determination of a case. According to the Roman law of the republic, the intervention of the a. - also called comes, iuris studiosus, consiliarius - was by no means obligatory and was left on each occasion to the discretion of the judge; later, especially in the imperial provinces, the assessorship became an institution of a permanent character. In canon law, the a. had the role of consultant, called, when necessary, to elucidate the points of a particular dispute (c. 11, de rescriptis, I, 3, in VI); and he is likewise regarded by the current Code, which (can. 1575) permits a single judge - and, it should be noted, not a collegiate tribunal - to be assisted with a consultative vote by no more than two assessors, chosen from among the synodal judges. The a. takes an oath in accordance with can. 1622 and is bound to official secrecy under can. 1623.
The first senior official of those three Sacred Congregations (the Holy Office, the Concettoriale, and that for the Oriental Church) which have the Pope as prefect is also called a. (v. CONGREGAZIONI ROMANE, SACRE). In rank, functions, and privileges he is assimilated to the secretaries of the other Congregations (cf. Const. Ad incrementum decoris of Pio XI, 16 Aug. 1934).
In Italian law, the members of the municipal executive council are called a.; and this name was also given, from 1931 to 1945, to the five lay judges of the Courts of Assize.