We turn now to chapter five.
Afer Scribens Afris:
The Church in Augustine and the African Tradition
Augustine had returned to Africa after spending years in Italy — that is, after being immersed in an Italian (Roman, Milanese) church culture that was at odds with the African one. The Italian church was “a cosmopolitan Church, wielding wide influence over emperors and officials, occupying a place of leadership in society, confident of its power to absorb, mould and transform it.”  By contrast, the African church saw itself “as an alternative to worldly society and as a refuge from it. […] African Christians had come to think of the Church as standing uncompromisingly over against an alien and hostile world.”  The African tradition had roots in Tertullian (ca. A.D. 155-ca. 240 and Cyprian (ca. A.D. 200-258).
Figures like Tertullian saw ” ‘world’ and ‘Church’ [as] mutually exclusive. If the ‘Church’ allowed itself to be penetrated by ‘world’, then the threshold of the sanctuary had to be moved back to a point beyond the reach of contamination, to a realm where the purity of the Spirit would hold sway.”  This model “was the outcome of a stark dichotomy  between [the Church’s] ‘truth’, ‘purity’ and ‘holiness’ ranged against [the world’s] ‘error’ and ‘idolatry’.” If the Church failed to maintain herself in such a posture based in such a dichotomy, she “could not be the true Church.” This problem became acute after the 3rd-century persecutions, when the Church in Africa (also in Rome, Egypt and Palestine) became divided on how to deal with traditores (Latin for those who handed over, the origin of our English word “traitor”), those who had in some way betrayed the community, whether by handing over something or someone to the Empire for death or destruction, or by making some gesture of sacrifice to the Emperor or the Roman gods. Without an institutional anchor to resolve where the Church is in the case of a split, those who claimed to lack the pollution of having “reconciled” traditores in their midst could say they were the “pure”, “true” Church.
Cyprian “was the intellectual heir of Tertullian.”  Once he had elaborated Tertullian’s puritanical ideal by anchoring the Church-of-the-pure in an episcopal structure, the question of traditores focused on traitor bishops. Cyprian taught that as for lay purity, “[t]here are sure to be tares among the wheat, and [these] must be tolerated.”  Clerical purity was another matter: “[s]in and impurity disqualify the minister and invalidate his ministry”.  The faithful are to separate from such ones. The sacraments of such clergy cannot sanctify; this “fixes a gulf between the Church and the world”. With such a strict boundary, rebaptism of those “outside” became the norm. In A.D. 256, Pope Stephen failed to persuade the African church to abandon the practice of rebaptism.  The Donatists claimed to have had no traditores in their line of episcopal ordinations, and so, unlike sectarians in other areas of the world, Donatists could claim to be the Church in Africa itself. When the African church appealed to Constantine to resolve a dispute about the succession for the See of Carthage, imperial law accomplished what Pope Stephen could not, and declared rebaptism heretical. Overnight, the African heirs of Cyprian became schismatics because of a foreign decision.  They felt betrayed by this newly-designated “Catholic” church overseas, which “failed to make much headway” in Africa.
The Donatists maintained that the ordinations of the Catholics were illegitimate, because they had traditores in their ordination line. “But the historical facts […] conceal the real issue in the conflict”, which was not about “the origins of the two [c]hurches, but what they actually were.”  Augustine agreed to anathematize any traditores in the Catholic patrimony,
but we shall not on that account relinquish the Church… 
“What was at stake was the right way of conceiving the Church and of representing it in relation to the world.” [112, 122] “For the Donatists, [Church and world] were mutually exclusive alternatives” , with the Church being the social sphere of the sacred, and the secular/worldly being “irretrievably”  the sphere of the profane. The Donatists were still locked into “a stance of permanent hostility”, and their sacramental theology (“all light, purity and godliness within[;] darkness, sin and godlessness without” ) reflected this, as it was “no more than the application of the old doctrine of the Church as the sole and exclusive abode of holiness.”  As we saw with Eusebius and Prudentius, Catholics of the Constantinian establishment saw themselves as the agents and recipients of a changed, future world prophesied by the Old Testament, while the Donatists saw themselves as the heirs to a local, past tradition of purity. As Augustine portrayed the difference,
The clouds of heaven proclaim the house of God being built over the whole earth; and the frogs croak from their pond: “We only are Christians.” 
The two parties met at the Conference of Carthage in 411, at the command of the (Western) Emperor Honorius, with an eye to resolving the division. It ended with a mandate for the suppression of Donatism.
Markus earlier noted that Augustine “learned much”  from a Donatist theologian, Tyconius. Tyconius “had been excommunicated by the Donatists for rejecting”  their concept of a “pure” Church, and consequently their practice of rebaptism. Nonetheless, he did not become Catholic, seeing the “Constantinian settlement, and the Church dependent upon it in Africa, [as] the work of Antichrist.”  The “Catholics”, he maintained, had betrayed the martyrs by “identif[ying] with the Empire”. Prompted by this, Augustine came to see that “the stark antithesis between iniquity and righteousness […] could not be expressed […] in sociological categories.” The sense of the Church’s holiness must make room for sinners within it, as Tyconius knew, and her holiness “is not invalidated”  by sinners in her. “Tyconius was the first to have elaborated a theology of the Church’s holiness as eschatological.” Saints and sinners within the Church could not be separated until the Eschaton. This is “the foundation” of Augustine’s two cities.
Just as what we would call the “state” contains members of both cities, united in love of proximate goods for either worldly or ultimate reasons, so too does the Church contain members of both cities. The Church is not simply identical with the heavenly city, against the Donatist ideal. The parallels between the secularization of the state and the secularization of the Church begin to break down here, however. The question “where does Rome belong in the scheme [of the two cities]?” is different from “given the identity of the Church and the ‘heavenly city’, where is the ‘earthly city’ to be found within the Church?”  “[I]n any given society on earth, both ‘cities’ must have their members.” With this Tyconian insight, Augustine both affirmed and reinterpreted the Cyprianic model of the Church. “The Church could therefore be  said to be the City of God in a way in which a state could not be identified […] with the earthly city.” Markus summarizes:
Idolatry or the lust for power might disfigure a state such as the Roman, and thus identify it with the earthly city; but in a sense this identity is accidental. Rome, or some other state, may in fact be idolatrous, but it is not defined as a state by its idolatry or its lust for power; whereas it is just such a permanent and essential link which identifies the Church with the City of God. A state, simply as such, without some disfiguring idolatry, for example, being written into its constitution, is neutrally ‘open’ to both cities. […] [It] can be assimilated to one or other city only in virtue of its citizens’ allegiances; and these, one must assume, are generally an unpredictable mixture. […] [T]he Church is not neutrally ‘open’ to both cities in the way the state is. It is identical with the City of God in a way in which no other human grouping can be with either city. […] The Church is the historically visible form of the City of God. 
Yet despite this, the Church is still not holy as a social group, and, within the saeculum, contains members of the earthly city. This is the African patrimony in Augustine via Tyconius: the Church is not holy in an “empirical, sociological or historical”  sense, but in an eschatological one. “Though identical with the City of God, there is room in it, for the time being, for the earthly city, too.” This is against the Donatist claim: the world and the Church “are co-extensive: there is a real distinction to be drawn between them, but it is eschatological rather than sociological or historical.”  Augustine’s “image of the Church is that of a ‘secular’ institution” , described in the same language as “the Bible applies to the ‘world’.”  This is because “the Church is the world, the world reconciled in Christ.” The Donatist secular out-group vs. churchly in-group became “what ‘is now’ vs. what ‘shall be’.” The most important distinction is no longer between groups, but rather cuts across groups, and through every person.
Thus, neither the act of persecuting nor the fact of being persecuted assimilate a figure or an institution to either city. “The enemy is rarely external”. As Augustine writes,
Within, that which is of the Devil is to be repudiated; and outside, that which is of Christ is to be acknowledged. 
This mixed state, both within the Church and without, are characteristic of the ambiguities of the saeculum. Distinguishing the Church from the world “was no simple matter of labelling empirically circumscribable human groups.”  The Church is eschatological, and so is not identical “with any worldly institution”, and no worldly institution can be called sacred. The distance between the eschatological city of God and “any historical society, past, present or future, was infinite.”  No earthly society can be modeled on the heavenly city. “The bottom has fallen out of any theology of a sacral society, and with it, of the Constantinian establishment.” 
Then there is the final matter of the Roman See. Having a “will to independence” , “Africa certainly never sold out to Rome.”  As Augustine followed the African tradition, without feeling the need to justify it, “there are only stray hints”  to indicate his attitude towards the papacy. When the African bishops wrote to Pope Innocent concerning Pelagius, discovering that he enjoyed favor in Rome, they wrote with “deference”, hoping “to spur [him] into action.” In Augustine’s letter, he wrote of the Church as “an irrigation system.” The “source of the fertilising waters was not, of course, the Roman Church, but the one Lord, the one faith and the apostolic Church” ; Augustine simply wished to confirm that they were drawing on the same stream. The Roman papacy, however, saw itself “as […] the ‘source of waters'”, in conflict with this older, African use of the irrigation metaphor. So Augustine, in addressing the Matthean (Matt 16:18) image of Peter as the rock upon which the Church is built, writes that Peter there signifies
the whole Church …whose person he represents by his symbolic universality. 
Resisting the papal subversion of the stream metaphor. “On the one occasion when Augustine speaks about Rome as the source of true teaching,” he is thinking of the Vergilian sense of Rome as the caput orbis, the head of the world. He never laid out a conciliar response to monarchical claims. Although “the bishops of Rome […] since the 360s […] were seeking to transform the Roman See into the ‘head’ of the Church” , and although this made “triumphal headway” in Western Europe, Africa, however, resisted — so much so that Pope Gregory the Great would interpret “the fierce independence of these churches” , who would cite Augustine as grounds for independence, “as a revival of Donatism.” Africa fell to the Arabs before the opening of the eighth century, however, leaving Rome without any real opposition in the West, and “gaining” Rome “undisputed status”.