=16. Mariology.=--In the _Decreta Gen._, ii, 4, are prohibited (in 1617) all works in which the contention is maintained that Mary had partaken of any earthly sin. It is the conclusion of the Church that those who maintain that Mary had any part in such sin are heretics and godless ones (_impii_). This prohibition stands in the Index of Alexander VII under the term _libri_. It is cited from a Bull of this Pope issued in 1661. In 1617, Paul V caused the Inquisition to prohibit the presentation in sermons, lectures, or theses of any suggestion concerning the possible sinfulness of Mary. Paul takes pains to add, however, that his prohibition is not to be considered as undertaking itself to present a final conclusion on the question. It is the case that the several Indexes include the titles of a long series of books in which the doctrine of the Immaculate Conception is defended. The ground for the prohibition of books presenting this doctrine has been the tendency to misapprehensions and misstatements in the form of presentation. It appears that the Dominicans, who have controlled the policy of the Inquisition and largely that also of the Congregation of the Index, have had the chief responsibility for the condemnation of all doctrinal treatises which did not present precisely according to the Dominican theories the doctrine of the Immaculate Conception. A number of other works on Mariology are forbidden on the ground of exaggerations of statement, of bad taste in expression, and of confusion in the analyses of doctrinal issues. Among the worst of these is a treatise of Maria of Agreda and one by J. B. Poza. There are also in the Index a group of writings condemned on the ground of their exaggeration of the worship of Mary.