He edited or explained many works of the
patristic and
medieval writers, and composed erudite
treatises on most diverse subjects.
Carlos Sommervogel enumerates two hundred and twenty-nine titles of
printed works and thirty-nine
manuscripts attributed to Gretser, but it is convenient to follow the grouping of his writings as they are distributed in the seventeen
folios of the complete edition which appeared in
Ratisbon (1734–1741). • Vols. I-III contain archaeological and theological disquisitions concerning the Cross of Christ • IV-V, a defence of several ecclesiastical feasts and rites • VI-VII, apologies for several Roman pontiffs • VIII-IX, a defence of Bellarmine's writings, to which vol. X adds a defence of some lives of the Saints • XI, a defence of the Society of Jesus • XII, polemics against the
Lutherans and
Waldenses • XIII, polemic miscellanies • XIV-XV, editions and translations of Greek ecclesiastical writer • XVI-XVII, philological works The first volume, for instance, contains five books treating successively of the Cross on which
Jesus Christ died, of images of the cross, of apparitions of the Holy Cross, of the sign of the cross, and of the spiritual cross. The second volume gives fifty-seven Graeco-Latin
eulogies of the Holy Cross by
Greek writers; the third treats of cross-bearing coins, of the
Crusades, adding also a defence of both the Crusades and the veneration of the Cross. ==References==