During seasons of great pestilence men have often believed the prophecies of crazed fanatics, that the end of the world was come. Credulity is always greatest in times of calamity. Prophecies of all sorts are rife on such occasions, and are readily believed, whether for good or evil. During the great plague, which ravaged all Europe, between the years 1345 and 1350, it was generally considered that the end of the world was at hand.