Augustine challenged the Donatist heresy, which during the late fourth and early fifth century posed Roman Catholic Christians against more zealous Christians in North Africa. He was a theological champion of the church who already was on site when the Donatist controversy was coming to a forceful conclusion at the end of his life. It threatened both his life and the very existence of his diocese of Hippo. While the battle of Augustine with the Pelagians was mainly a theological one fought with the intellect, the battle with the Donatists was more direct. In comparison, if his contest with the Pelagians was a debate, then his contest with the Donatists had some of the disturbing aspects of a riot as well.
When Augustine came to Hippo, the Donatist schism had existed for about a century. Donatism had been around since the persecutions under Diocletian, when Christians were ordered to turn over their Scriptures to Roman authorities. Some had obeyed this order. Others had absolutely refused, and had suffered torture or death as a result. Many did something in between, such as hiding or fleeing. After the persecution ended, the church had to decide how to treat people - especially bishops - who had handed in their books and holy objects for destruction (i.e., they became what was called a traditor - a Latin word for one who "hands something over") or had fled so as to avoid persecution.
If a bishop had complied with the order or had fled, could he again serve as a bishop once the danger was over? Or if he had lost his credibility with his people for being a traditor, should he be removed from office? Should he be retained in office, were his subsequent sacramental acts valid? If he had ordained a priest or helped consecrate another bishop, were their orders valid? The church was split over these matters, especially in North Africa.
The Donatist schism had sprung out of the persecution of the Christian church by Diocletian in the beginning of the fourth century. In about the year 412, forty years before Augustine was born, some members of the Church in Carthage were fired with fanatical zeal on behalf of those who had distinguished themselves by resistance to the imperial mandates and courted martyrdom. These members now resented deeply the appointment of a bishop of moderate opinions. They claimed that the consecration of this church leader been performed by one who was a traditor, i.e., one who had not defended the Faith strongly enough.
They held that those who denied the Faith could never be forgiven subsequently. Behind their objection lay the false belief that only those living a perfect life belonged in the church, and, further, that the validity of any sacrament depended upon the personal virtue of the priest or bishop who administered it. They set up, in consequence, a bishop of their own, of the name of Majorinus. He was succeeded in 315 by Donatus, after whom Donatism received its name.
The party made great pretensions to purity of discipline, and rapidly rose in popular favour notwithstanding a decision given against them both by the Pope in Rome and by the Emperor Constantine, to whom they personally appealed. The Donatists thus in the year 312 selected their own rival Bishop of Carthage in the person of Donatus.
Their practice of rebaptising "converts" from the Roman Christian church was particularly abhorrent to the Roman and North African church. The Donatists were condemned by the Synod of Arles in the year 314. and also by Constantine I, who was the Roman emperor. When they refused to submit, Constantine ordered the army to force them into submission. This was possibly the first official use of military force carried out in favour of the Christian religion.
The Donatists suffered death with the same zeal as the early Christian saints had done. They were perfectly willing to die at the hands of a Christian emperor, but this use of the secular power seemed no more successful than that of the Emperor Diocletian had been in the years 303 to 305. The action by the Emperor against the Donatists was an indication of the way they had prospered and become a dominant element in Africa. For example, when Constantine built a basilica for the Catholics in the town of Cirta, the Donatists took it over. Constantine was forced to build the Catholics another one.
The Donatists left the official Catholic Church in the year 316 (i.e., forty years before the birth of Augustine), and set up their own network of Donatist bishops and dioceses. By 321 the Emperor Constantine had ordered an end to state action against the Donatists. He justified himself on the grounds that punishment was to be left to God. By the year 330 the Donatists had 270 bishops in North Africa. Keep in mind, however, that because of the difficulty of travel in those days, and because preaching was done only by bishops (but not by priests, except for Augustine), even in the Roman Catholic Church there a diocese was more like the size of what would be called a parish today.
By the year 350 the Donatists outnumbered the orthodox Christians in Africa. Each city (including the diocese of Hippo) had its opposing orthodox and Donatist bishops, and in Hippo Donatists were numerically greater and more influential locally than were the Christians faithful to Rome. The response and behaviour of Augustine to Donatism was coloured by this disturbing (for him) reality.
The effect of Donatism upon Augustine
The fight against Donatism took up much of the time of Augustine. His combat against it definitely influenced his theology. After his consecration as Bishop of Hippo in 395-396, Augustine had devoted continual attention for more than ten years to the challenge of Donatism. He had done this in numerous sermons, letters, and other treatises having to do with the nature of the church and the sacraments. In doing this, he had articulated, much more fully than had ever been done before, the doctrine of the church. And, although the Donatist controversy brought out some of what is regretful in the legacy of Augustine, it also prompted his greatest theological achievements. It was partly responsible for prompting scholarly exposition, his major book, the City of God. Augustine is criticised for his handling of the Donatist controversy. He used the political and legal power of the Roman Empire to suppress the Donatist church. From his point of view, however, this was his attempt to compel the Donatists to come back to the Catholic Church.
It is important to note that he never called for the Donatists to be tortured or executed as heretics. The Donatist movement had essentially gone from North Africa by the time of the death of Augustine in the year 430. Paradoxically, this triumph of the Roman church in North Africa proved to be brief, for it in turn faded in North Africa with the arrival of the Vandals. They were barbarians who were militant Arian heretical Christians, and fanatically anti-Catholic.
Whereas in the year 411 North Africa had 286 Catholic bishops and 279 Donatist bishops, after the Vandal - Arian persecutions in 525 AD the number of Catholic bishops was only 60. In the year 533 the Eastern Roman Empire (Byzantine) invaded the area, and the Islamic Arabs took over from them in the seventh century. By the end of the seventh century the area was largely Muslim. This situation is still essentially the case today, over 1,300 years later.
Donatism. A one-page summary. http://www.infoplease.com/ce6/society/A0815846.html
Donatism. From the first edition of the Catholic Encyclopedia. Lengthy. http://www.newadvent.org/cathen/05121a.htm AN1207