mands of the bishops, and the decrees of Councils in a similar direction.
Historical documents bear special witness to the care and diligence with which the Roman Pontiffs have vigilantly endeavored to prevent the unchecked spread of heretical writings detrimental to the public. History is full of examples. Anastasius I solemnly condemned the more dangerous writings of Origen, Innocent I those of Pelagius, Leo the Great all the works of the Manicheans. The decretal letters, opportunely issued by Gelasius, concerning books to be received and rejected, are well known. And so, in the course of centuries, the Holy See condemned the pestilent writings of the Monothelites, of Abelard, Marsilius Patavinus, Wycliff, and Huss.
In the fifteenth century, after the invention of the art of printing, not only were bad publications which had already appeared condemned, but precautions began to be taken against the publication of similar works in the future. These prudent measures were called for by no slight cause, but rather by the need of protecting the public morals and welfare at the time; for too many had rapidly perverted into a mighty engine of destruction an art excellent in itself, productive of immense advantages, and naturally destined for the advancement of Christian culture. Owing to the rapid process of publication, the great evil of bad books had been multiplied and accelerated. Wherefore Our predecessors, Alexander VI and Leo X, most wisely promulgated certain definite laws, well suited to the character of the times, in order to restrain printers and publishers within the limits of their duty.
The tempest soon became more violent, and it was necessary to check the contagion of heresy with still more vigilance and severity. Hence Leo X, and afterwards Clement VII, severely prohibited the reading or retaining of the books of Luther. But as, owing to the unhappy circumstances of that epoch, the foul flood o
