When the Empire adopted Christianity, it had therefore the traditions of the Mosaic law and the first chapter of the Epistle to the Romans to guide its legislators on this topic. The Emperors felt obscurely that the main pulses of human energy were slackening; population all tended to dwindle; the territory of the empire shrank slowly year by year before their eyes. As the depositaries of a higher religion and a nobler morality, they felt it their duty to stamp out pagan customs, and to unfurl the banner of social purity. The corruption of the Roman cities had become abominable. The laziness and cowardice of Roman citizens threatened the commonwealth with ruin. To repress sexual appetites was not the ruler's object. It was only too apparent that these natural desires no longer prompted the people to sufficient procreation or fertility. The brood begotten upon Roman soil was inadequate to cope with the inrushing tide of barbarians. Wisdom lay in attempting to rehabilitate marriage, the family domestic life. Meanwhile a certain vice ran riot through society, a vice for which Jehovah had rained fire and brimstone upon Sodom, a vice which the Mosaic code punished with death, a vice threatened by St. Paul with "that recompence of their error which was meet." Justinian, in 538 A.D., seems to have been terrified by famines, earthquakes and pestilences. He saw, or professed to see, in these visitations the avenging hand of Jehovah, the "recompence which was meet" mysteriously prophesied by St. Paul. Thereupon he fulminated his edict against unnatural sinners, whereby they were condemned to torments and the supreme penalty of death. The preamble to his famous Novella 77 sets forth the principles on which it has been framed: "Lest as the result of these impious acts whole cities should perish together with their inhabitants; for we are taught by Holy Scripture, to wit that through these acts cities have perished with the men in them.... It is on account of such crimes that famines and earthquakes take place, and also pestilences." Before Justinian, both Constantine and Theodosius passed laws against sexual inversion, committing the offenders to "avenging flames." But these statutes were not rigidly enforced, and modern opinion on the subject may be said to flow from Justinian's legislation. Opinion, in matters of custom and manners, always follows law. Though Imperial edicts could not eradicate a passion which is inherent in human nature, they had the effect of stereotyping extreme punishments in all the codes of Christian nations, and of creating a permanent social antipathy. II. VULGAR ERRORS.