This great revolution, which profoundly affected the moral condition of Italy, had long been impending. The debts of the poor peasants, and the tendency of the patricians to monopolise the conquered territory, had occasioned some of the fiercest contests of the Republic, and in the earliest days of the Empire the blight that seemed to have fallen on the Italian soil was continually and pathetically lamented. Livy, Varro, Columella, and Pliny have noticed it in the most emphatic terms,(447) and Tacitus observed that as early as the reign of Claudius, Italy, which had once supplied the distant provinces with corn, had become dependent for the very necessaries of life upon the winds and the waves.(448) The evil was indeed of an almost hopeless kind. Adverse winds, or any other accidental interruption of the convoys of corn, occasioned severe distress in the capital; but the prospect of the calamities that would ensue if any misfortune detached the great corn-growing countries from the empire, might well have appalled the politician. Yet the combined influence of slavery, and of the gratuitous distributions of corn, acting in the manner I have described, rendered every effort to revive Italian agriculture abortive, and slavery had taken such deep root that it would have been impossible to abolish it, while no emperor dared to encounter the calamities and rebellion that would follow a suspension or even a restriction of the distributions.(449) Many serious efforts were made to remedy the evil.(450) Alexander Severus advanced money to the poor to buy portions of land, and accepted a gradual payment without interest from the produce of the soil. Pertinax settled poor men as proprietors on deserted land, on the sole condition that they should cultivate it. Marcus Aurelius began, and Aurelian and Valentinian continued, the system of settling great numbers of barbarian captives upon the Italian soil, and compelling them as slaves to till it. The introduction of this large foreign element into the heart of Italy was eventually one of the causes of the downfall of the empire, and it is also about this time that we first dimly trace the condition of serfdom or servitude to the soil into which slavery afterwards faded, and which was for some centuries the general condition of the European poor. But the economical and moral causes that were destroying agriculture in Italy were too strong to be resisted, and the simple habits of life which agricultural pursuits promote had little or no place in the later empire.