2. It is the nature of crime to perpetuate itself, and the atrocities of the Greeks brought about a retaliation from the Latins. Twenty years after the events I have been relating, the Crusading hosts turned their arms against the Greeks, and besieged and gained possession of Constantinople; and, though their excesses seem to have been inferior to those which provoked them, it is not to be supposed that a city could be taken by a rude and angry multitude, without the occurrence of innumerable outrages. It was pillaged and disfigured; and the Pope had to publish an indignant protest against the work of his own adherents and followers. He might well be alarmed and distressed, not only for the crime itself, but for its bearing on the general course of the Crusades; for, if it was difficult under any circumstances to keep the Greeks in a right course, it was doubly difficult, when they had been injured, even though they were the original offenders. 4. 3. But there were other causes, still less satisfactory than those I have mentioned, tending to nullify all the Pope's efforts to make head against the barbarian power. I have said that the period of the Ottoman growth was about 270 years; and this period, viz., the fourteenth and fifteenth and first half of the sixteenth centuries, was the most disastrous and melancholy in the internal history of the Church of any that can be named. It was that miserable period, which directly prepared the way for Protestantism. The resistance to the Pope's authority, on the part of the states of Europe generally, is pretty nearly coincident with the rise of the Ottomans. Heresy followed; in the middle of the fourteenth century, the teaching of Wickliffe gained ground in England; Huss and others followed on the Continent; and they were succeeded by Luther. That energy of Popes, those intercessions of holy men, which hitherto had found matter in the affairs of the East, now found a more urgent incentive in the troubles which were taking place at home.