THEOLOGIAN CANON. — In every cathedral church there must exist the office of theologian canon, which may also be established in collegiate churches, especially eminent ones (can. 398, § 1). If there is no incumbent capable of fulfilling this task, at least the office itself must be established.
1. The office of theologian canon originated under the pontificate of Innocent III in a decree of the Fourth Lateran Council (1215), worded as follows: «In every metropolitan church a theologian shall be designated, whose mission is to interpret the Sacred Scriptures and to teach the faithful what is the object of the pastoral ministry» (L. Thomassin, Antiqua et nova disciplina Ecclesiae circa beneficia, Lucca 1728, I, cap. 1; II, cap. 10, n. 1). This decree, extended to cathedral churches by the Council of Basel, was solemnly promulgated by the Council of Trent (sess. V, c. 1). For this office, the person who, in view of local circumstances, proves most suited to carry out these functions shall be chosen: other things being equal, a doctor, and preferably a doctor of theology, shall be designated (can. 399, §§ 1-2). Following Pius XI’s motu proprio «Bibliorum scientiam» of 27 April 1924, the theologian canon, charged with explaining Sacred Scripture to the faithful, must have obtained academic degrees from the Biblical Commission or at least have received the title of bachelor from the Biblical Institute of Rome (AAS, 16 [1924], pp. 180-82).
2. On the days and at the hours fixed by the bishop after consulting the Chapter, the theologian canon shall publicly explain Sacred Scripture in the cathedral or collegiate church. Should he deem it appropriate, the bishop may entrust the incumbent with teaching other branches of Catholic doctrine, such as dogma and moral theology. It should be added that, for a grave reason, the theologian canon may be called upon to teach the sacred sciences in the seminary instead of delivering these lessons in church: such a grave reason exists when the bishop finds no other professor competent for the purpose. In this case, the theologian canon who obeys his bishop is considered equally to be exercising the functions of his office and loses none of his canonical rights (can. 420, § 1, n. 2).
3. The theologian canon, like all canons, is appointed by the bishop, unless in certain chapter churches the choice is subject to a competitive examination; wherever this system exists, it is to be preserved (can. 399, § 2).
4. The theologian canon shall perform his functions personally; or, if prevented from doing so for a period exceeding six months, he is obliged to have himself replaced at his own expense by another priest whom the bishop shall designate (can. 400, § 2).
The canonical sanctions are the same as those of the penitentiary canon (v. can. 2384).