The return of Augustine to Africa marks the beginning of the second of the two major divisions of his life. Out of his novitiate he passed into his ministry.

He spent three years in monastic seclusion, though not in solitude. He kept a group of friends about him. They lived on the farm which had been the property of his father. There they set the example in Africa of that spiritual discipline which Basil and Gregory had practised in the East, and Martin and Cassian and Jerome had preached in the West.

After three years of this delightful quiet, being on a Sunday in the neighboring town of Hippo, the bishop of that place in his sermon reminded the congregation that he was growing old and feeble, and that being himself a Greek it was particularly hard for him to preach in Latin. The people, understanding what was in his mind, seized upon Augustine whose holy life they knew, and demanded that he become the bishop's assistant. To this he reluctantly consented. He was ordained, and entered upon his duties. By and by, the bishop died, and Augustine became bishop of Hippo in his place. There he continued forty years, all the remainder of his life.

Hippo is still a populated place, in Algiers, two hundred miles west of Tunis. The neighborhood is singularly suitable for the observation of eclipses of the sun, and thereby invites the visits of both English and American astronomers. An aqueduct of the time of Hadrian remains from the town which Augustine knew. The city in his day had a wall about it, and its inhabitants were sixty thousand. The great Basilica, his cathedral, stood on high ground in the midst of the city, among almond and orange trees, looking towards the sea and the far hills of Tunis. In 1890, Cardinal Lavigerie consecrated a new cathedral on the site of the old, naming it in memory of him who is still spoken of, even by the Mohammedan inhabitants, as the Great Christian.

There Augustine went about his business as a bishop. In all simplicity, without ostentation, in a day when bishops lived like princes, he ministered to the fishermen of Hippo. With much strictness of personal abstinence, he maintained a modest hospitality. A sentence carved on the table in his dining-room reminded his guests that as for those who were disposed to speak unfriendly of their neighbors, their room was better than their company. He gathered his clergy about him, to live under his own roof. He required them to follow that ascetic life in which he set them an example. He forbade them to have private property, or to be married. He set forth for their guidance a rule of life, adapted to those who having their daily occupation in the world were intent on the improvement of their souls. In the eleventh century, this rule, or what was thought to be this rule, was adopted by the clerical order of Augustinians, the Austin Canons, in whose house at Erfurt Martin Luther studied the Bible and prepared himself to undertake the German Reformation.

In the midst of these quiet labors came three determining events: two controversies and a great calamity.

The controversies, one with the Donatists, the other with the Pelagians, were characteristic of the Christianity of the West. The Western Church had regarded the Arian Debate with perplexity and impatience. The discussion had been carried on in Greek, a language with which the West was imperfectly acquainted. The General Council at Nicæa under Constantine, which proclaimed the Nicene faith, and the General Council at Constantinople under Theodosius, which confirmed it, had been remote from the concerns of Europe. There were but seven Western bishops at Nicæa, and none at all at Constantinople.

Moreover, the theme of the debate had been foreign to the active and practical interests of the Western mind. The Eastern bishops of eminence were for the most part theologians, of a speculative habit of thought; the eminent bishops of the West were for the most part ecclesiastics, administrative persons. Thus while the Eastern Church was vexed with heresies, arising from differences in theology, the Western Church was vexed with schisms, arising from differences concerning organization. And when a notable heresy did appear in the West,—the Pelagian,—it was concerned not with the nature of God, but with the nature of man: it had to do with practical human life.

Against the erection of a complete and exclusive organization, the Donatists had long since protested. They had now been a separate church for nearly two hundred years. They were especially strong in Africa. There were Donatist churches side by side with the Catholic churches in Hippo. So intimate was the contention that no Donatist woman would bake a loaf of bread for a Catholic. And there was frequent violence.

Augustine at first addressed himself to the reconciliation of this inveterate division. But the original arguments for and against were now so entangled with prejudices, so complicated by years of abusive controversy, and so lost under an increasing burden of fresh grievances, that no friendly settlement seemed possible. The cruelties of imperial soldiers against the Donatists had been answered with fierce reprisals. In Augustine's own time and neighborhood, one Catholic bishop had been ducked in a pond, and another had been beaten about the head with the pieces of his broken altar. Augustine himself was in frequent peril.

In his books against the Donatists, Augustine shows the effects of this contention. First of all great Christian teachers, he formally defended the persecution of heretics. The shedding of the blood of the Priscillianists had indeed been undertaken at the instigation of bishops, but other and better bishops had deplored it. Here, however, were heretics destroying churches and assaulting clergy. Their evil must be met with evil. Their violence must be resisted with violence. Augustine tried in vain to keep the precepts of the Sermon on the Mount. He was disposed to love his enemies. But he hated the Donatists. They seemed to him to be outside the limits of Christian forbearance. He advised treating them as thieves and robbers should be treated. In a writing entitled "De Correctione Donatistanum," he held that the civil power ought to restrain schism. He was the first to translate the hospitality of a parable into the hostility of a religious war, and to find a sanction for persecution in the words "Compel them to come in." He might as well have taken for a text, "Rise, Peter, kill and eat!" The principle proceeded easily from the punishment of wrong acting to the punishment of wrong thinking. Augustine became an apostle of intolerance. Thus the controversy with the Donatists continued until all the clamorous voices were silenced, in the year when Augustine died, by the victorious invasion of the Vandals.

The heresy of the Pelagians turned upon the question, How may we be saved from sin? An answer was given by a Briton, named Pelagius. He said, "We may be saved by being good." He quoted the words of Jesus, "If thou wilt enter into life, keep the commandments." Anybody, he said, can do that, if he tries hard enough. The church is not necessary, the sacraments are not necessary, the grace of God is not necessary. These are all helpful, but not essential. Be good: this is the desire of God, and it is possible to every child of God.

The matter became a subject of controversy in connection with the letters of congratulation which were written to Demetrias, a young Roman lady who had entered the monastic life. Jerome said that this was the most important event in the history of Rome since the defeat of Hannibal. But Pelagius was not so enthusiastic. He acknowledged the excellences of the single life, but observed that there was danger of overestimating them. Men and women could be holy, if they would, under any conditions. The natural life was as acceptable to God as the ascetic life. He praised the innate goodness of human nature, and protested against the theory that man's will is totally corrupt.

The letter precipitated a general discussion, and Pelagius, a sweet-tempered, simple-hearted person, who in his own experience and observation had encountered much more good than ill, found that he had drawn upon himself the fire of the great guns of Augustine.

Never has the personal equation entered more evidently into the progress of thought. To Augustine, with his hot African nature, remembering his own participation in the wickedness of the world, the supreme fact of human life is sin. Taking his clue from expressions of St. Paul, he traced it back to the first man. The spring of humanity was poisoned at its source. Every human being is born bad. The race is lost, and every member of it, by nature inclined to evil, is not only unable to do good, but is doomed, in consequence of this inability, to everlasting punishment.

Accordingly, salvation cannot come by any effort of our own. It must be derived from without. In his teaching as to the source of salvation, Augustine presented his two characteristic doctrines.

The first doctrine was that salvation comes by grace. Grace is help from God. To a part—a small part—of our doomed race, by reason of the act of His inscrutable will, God gives grace, and they are saved. The sacrifice of Christ upon the cross makes grace available, but it becomes applicable to us not by any act of ours, not of ourselves. The saved were chosen of God, elect, predestinated to eternal life, before the world began.

The second doctrine was that grace comes by the church. It cannot be had outside the church. It is a subtle something which is imparted by the sacraments. Outside the church, then, among the schismatics, among the Donatists, is no salvation. All the heathen are lost. Infants dying unbaptized are not saved; they may be punished with some measure of mercy, and be damned with a somewhat mitigated damnation, but they cannot enter into heaven. The church is in the world as the ark floated on the flood. Unless we get in and stay in, we shall certainly be drowned in an ocean of everlasting fire.

The Pelagians said that Augustine's doctrines were immoral. If man has no free will, then he has no responsibility, and there is no difference between vice and virtue. They said that Augustine's doctrines were blasphemous. The condemnation of a race for the sins of one would be a horrible injustice, not to be attributed to God. They said that Augustine had been a Manichee, and had believed in a bad god, and had never been converted. But the church went with Augustine. In the breaking-up of the Roman Empire by the invasion of the barbarians, in the violence and misery of the time, in the prevalence of evil, in the face of the wicked world, he seemed a true interpreter of human life.

Toward the end of his long career Augustine did a curious and interesting thing. He published a good-sized book called "Retractations." In it he confessed the errors of his teaching. Concerning this matter and that he had changed his mind, in the better light of experience and truth. It was characteristic of his habitual humility and honesty. He did not retract, however, the positions which he took against the Donatists and the Pelagians. By virtue of these positions, he was the founder of Latin Christianity.

At last, in the midst of these controversies, came the great calamity of the fall of Rome.

Gradually, step by step, the barbarians had passed over the boundaries of the Danube and the Rhine into the empire. Constantine had held them in check, but after him they came in greater might than ever. They presented themselves as settlers, and were received as allies. These two aspects of their invasion dimmed the sight of the Romans regarding the tremendous changes which were taking place. Theodosius mastered them as long as his strong reign continued. After him his son Honorius reigned with incredible indifference in the West, and the barbarian Stilicho became his minister of state. And after Stilicho came Alaric.

Jerome writes in 409: "Innumerable savage tribes have overrun all parts of Gaul. The whole country between the Alps and the Pyrenees, between the Rhine and the ocean, has been laid waste by Quadi, Vandals, Sarmatians, Alans, Gepidi, Herules, Saxons, Burgundians, Allemans and, alas for the common weal, even the hordes of the Pannonians. The once noble city of Mainz has been captured and destroyed. In its church many thousands have been massacred. The people of Worms have been extirpated after a long siege. The powerful city of Rheims, the Ambiani [near Amiens], the Altrabtae [near Arras], the Belgians on the outskirts of the world, Tournay, Speyer and Strassburg have fallen to the Germans. The provinces of Aquitaine, and of the Nine Nations, of Lyons and Narbonne, with the exception of a few cities, have been laid waste. Those whom the sword spares without, famine ravages within. I cannot speak of Toulouse without tears. I am silent about other, places, that I may not seem to despair of God's mercy."

In 410 Alaric the Goth besieged Rome and took it. The eternal city, the immemorial metropolis of the world, the invincible and inviolable fortress of civilization, fell and was plundered by the Goths.

By the emperor Honorius, in his court at Ravenna, the news was received with that amazing indifference which was his most marked characteristic. He is said to have shown in his career only two signs of any interest in life: he had a strong sense of the importance of keeping his imperial person out of danger, and he had remarkable success in raising hens. Messengers brought the emperor the awful news. "Rome," they cried, "is destroyed!" "What!" he said, "only this morning she was feeding out of my hand "; and when they made him understand that it was the imperial city of which they spoke, he replied, greatly relieved, "Oh, I thought you meant my favorite hen, of the same name!"

But to Jerome at Bethlehem, Augustine at Hippo, and all other thoughtful Romans, it seemed to be, as indeed it was, the end of the age.

Then Augustine wrote his greatest work, the "City of God:" The purpose was to show that though the city of the world had fallen, the City of God stands strong forever. This writing is in twenty-two books. Ten are negative, showing the falsity of paganism: five to disprove that the present prosperity of man is dependent on the pagan gods; five to deny that they have anything to do with man's prosperity hereafter. Even in the fifth century, two hundred years after the conversion of Constantine, paganism was still of sufficient importance to call for this long and laborious refutation. The other twelve books are positive, setting forth the truth of the Christian religion: four about its origin, four about its growth, four to set in contrast the cities of the world secular and temporal, and the church, the city of the world spiritual and eternal.

With this work, the Early Church, and the Roman world with it, spoke its last word. After that, amidst the confusions and distresses of the barbarian invasion of the empire, the learning and literature of the time lapsed, for the most part, into the making of copies and compilations of previous opinions. Augustine's "City of God" served as a treasure house of theological material throughout the Middle Ages. It was a store of thought by which men lived in times of intellectual famine.

In 429, the Vandals under Genseric invaded Africa. Down they came over "the shining fields which had been the granary of Rome." In the common destruction of the country, the force of the invasion fell terribly upon the churches. When the Vandals came, Africa had five hundred bishops; twenty years after only eighteen dioceses had survived.

The invaders besieged Hippo. Augustine was in his seventy-fifth year. In the third month of the siege (430) he fell into a mortal sickness. The last of the fathers, the last of the great Romans, lay dying, as the empire, wounded beyond recovery, lay dying beside him. Outside the sickroom was the noise of fighting, and the shouts of the besiegers. Thus the city of his long service faded from Augustine's eyes, and he entered into that other city of which he wrote, the city of his hopes and prayers, the divine city, founded, as he said, on earth, but eternal in the heavens.