- Procopius, De Bellis and Historia Arcana (best edition by J.
For the Fourth Crusade the primary authority is Villehardouin's La Conquete de Constantinople, an official apology for the diversion of the Crusade written by one of its leaders, and concealing the arcana under an appearance of frank naïveté.
Besides the works already noticed, he wrote De arte critica (1597); De Antichristo (1605); Pro auctoritate ecclesiae in decidendis fidei controversiis libellus; Scaliger hypololymaeus (1607), a virulent attack on Scaliger; and latterly the anti-jesuitical works, Flagellum Jesuiticum (1632); Mysteria patrum jesuitorum (1633); and Arcana societatis Jesu (1635).
These remedies were arcana - a word corresponding partly to what we now call specific remedies, but implying a mysterious connexion between the remedy and the "essence" of the disease.
Arcana were often shown to be such by their physical properties, not only by such as heat, cold, &c., but by fortuitous resemblances to certain parts of the body; thus arose the famous doctrine of "signatures," or signs indicating the virtues and uses of natural objects, which was afterwards developed into great complexity.