Where can I read more about this?
Well, I suppose there are any number of places on the web, but if you wish simply read the letters of Cyprian that address this controversy with pope Stephen. Here's a sample below . . . he's speaking of Stephen as if he's speaking to him . . . Read the whole letter - it's too long to cite here . . .
Cyprian (c. 200-58): Consider with what want of judgment you dare to blame those who strive for the truth against falsehood. For who ought more justly to be indignant against the other?—whether he who supports God’s enemies, or he who, in opposition to him who supports God’s enemies, unites with us on behalf of the truth of the Church?—except that it is plain that the ignorant are also excited and angry, because by the want of counsel and discourse they are easily turned to wrath; so that of none more than of you does divine Scripture say, “A wrathful man stirreth up strifes, and a furious man heapeth up sins.” For what strifes and dissensions have you stirred up throughout the churches of the whole world!
Moreover, how great sin have you heaped up for yourself, when you cut yourself off from so many flocks! For it is yourself that you have cut off. Do not deceive yourself, since he is really the schismatic who has made himself an apostate from the communion of ecclesiastical unity. For while you think that all may be excommunicated by you, you have excommunicated yourself alone from all; and not even the precepts of an apostle have been able to mould you to the rule of truth and peace, although he warned, and said, “I therefore, the prisoner of the Lord, beseech you that ye walk worthy of the vocation wherewith ye are called, with all lowliness and meekness, with long-suffering, forbearing one another in love; endeavouring to keep the unity of the Spirit in the bond of peace. There is one body and one Spirit, even as ye are called in one hope of your calling; one Lord, one faith, one baptism; one God and Father of all, who is above all, and through all, and in us all.”
ANF: Vol. V,
The Epistles of Cyprian, Epistle 74, §24, p. 396. (This is Epistle 75 in the Migne Corpus)
Latin text: Vide qua imperitia reprehendere audeas eos qui contra mendacium pro veritate nituntur. Quis enim justius indignari contra alterum debuit? utrumne qui hostes Dei asserit, an vero qui adversus eum qui hostes Dei asserit pro Ecclesiae veritate consentit? Nisi quod imperitos etiam animosos atque iracundos esse manifestum est, dum per inopiam consilii et sermonis ad iracundiam facile vertuntur, ut de nullo alio magis quam de te dicat Scriptura divina:
Homo animosus parat lites, et vir iracundus exaggerat peccata. Lites enim et dissensiones quantas parasti per Ecclesias totius mundi? Peccatum vero quam magnum tibi exaggerasti, quando te a tot gregibus scidisti! Excidisti enim te ipsum. Noli te fallere; siquidem ille est vere schismaticus qui se a communione ecclesiasticae unitatis apostatam fecerit: dum enim putas omnes a te abstineri posse, solum te ab omnibus abstinuisti. Nec te informare ad regulam veritatis et pacis vel Apostoli praecepta potuerunt monentis et dicentis:
Obsecro ergo vos ego vinctus in Domino, digne ambulare vocatione qua vocati estis, cum omni humilitate sensus et lenitate, cum patientia sustinentes invicem in dilectione, satis agentes servare unitatem spiritus in conjunctione pacis; unum corpus, et unus spiritus, sicut vocati estis in una spe vocationis vestrae. Unus Dominus, una fides, unum baptisma, unus Deus et pater omnium, qui super omnes, et per omnia, et in omnibus nobis.
Epistola Firmiliant, Episcopi Caesareae Cappadociae, ad Cyprianum contra Epistola Stephani, PL 3:1173B-1174B.