Fragments of the First Letter to Pope Sixtus II

Previously indeed Stephen had written letters concerning Helenus and Firmilianus, and concerning all those established throughout Cilicia and Cappadocia and all the neighboring provinces, declaring that he would withdraw from their communion for that very same reason, namely that they rebaptized heretics. And consider the gravity of the matter. For in truth, as I hear, it has been decreed in the greatest councils of bishops that those who come from heresy should first be instructed in the catholic doctrine and then purged of the filth of the old and impure leaven through baptism. Concerning all these things I sent him letters entreating and beseeching him.

But also to our beloved fellow-presbyters Dionysius and Philemon, who previously agreed with Stephen, and had written to me concerning the same matters, I replied previously with a few words, but now with more.

For when, concerning the doctrine which was recently stirred up in the city of Ptolemais in the Pentapolis—impious and full of blasphemy against God almighty and the Father of our Lord Jesus Christ, full of unbelief and faithlessness toward His only-begotten Son and the firstborn of all creation, the Word made man, and which takes away the understanding of the Holy Spirit—when letters had been brought to me from both sides, and brethren had come to dispute the matter, I wrote certain letters, setting forth the matter as plainly as I could with God's gift; copies of which I have sent to you.