Luckily, not too many people are Jesus mythicists. The consensus among scholars is that Jesus really existed. There are a ton of reasons for this, but at least one reason is we have good reason to trust the reliability of the gospels. However, popular myths about the second century of Christianity still abound. Many times it is almost seen as a conspiracy: there was great diversity with no real “true” Christianity, but later orthodox Christians tried to cover this up. But, we can uncover the evidence they tried to suppress so now we know about their devious purposes. This view doesn’t align with the evidence. To see this, we will cover a wide range of areas about Christianity in the second century.
Michael Kruger titles his book Christianity at the Crossroads. The second century was important for shaping the future of the church. While the book is an introduction, in a brisk 230 pages he meticulously covers the second century by surveying the sociology, the acceptability among non-Christians, the ecclesiology, diversity, unity, literature, and canon. We will look at each of these areas in turn while attempting to balance his judicious choice of primary and secondary literature.
Christianity in the second century had a social makeup. All groups do. So we must ask what this was like for these early Christians. Here we will look at this topic in terms of the parting of the ways between Jews and Christians (to use later terms), socio-economic status, education, and sex.
The Parting of the Ways
One important point is that Christianity came into its own. Jesus and his early followers were Jews. They believed themselves to be good and faithful Jews, people who were obedient to Yahweh’s revelation. In following the Scriptural storyline, they believed the renewal of the Jews through the Messiah would lead to the nations joining in worshiping Yahweh. One can see this in restoration passages in Isaiah, Zechariah, and more. Then compare these with Jesus’ relation to non-Jews and his comments about who will “recline at table with Abraham, Isaac, and Jacob in the kingdom of heaven.” (ESV; see Matt. 8:5-13) Again, we see allusions to this already in early Christian literature like Paul referring to the church of God as a third category between Jews and Greeks (1 Cor. 10:32).
There were obviously deep disagreements between Jews who followed Jesus and those who did not. Kruger identifies four: Jesus shared in the divine identity, whether followers of Jesus were the true sons of Abraham, Gentile followers of Jesus did not have to follow the ceremonial laws, and Jesus followers began to criticize the continuing relevance of the temple, as Jesus did.  Combine this with the influx of Gentiles and political events involving Messianism and the destruction of the temple and you have a powder keg.
Pinning down when the parting took place can be difficult. Part of the difficulty is determining what exactly one means by parting. So, Kruger amasses a number of pieces of evidence that show that the beginning of the second century is when Christianity began to be seen as distinct from Judaism. Ignatius said it was “outlandish” to proclaim Jesus and practice Judaism. The Didache tells Christians to fast on different days in order to distinguish the two groups. The Epistle of Barnabas distinguishes between how Christians and Jews interpret the Old Testament and even uses terms like “us” and “them.” Justin Martyr in his dialogue with Trypho contrasts how Jews and Christians are saved. In the Martyrdom of Polycarp, Polycarp says “I am a Christian.”
Along these lines, you also see that the first century documents are largely worried about how Gentile converts relate to Judaism. In the second century they worry about how Gentile converts relate to paganism. There is also hostilities between Christians and Jews. This is well-known on the Christian side. At least among scholars, it is also known on the Jewish side with the Birkat Ha-Minim being one example. The curse reads, “Let Christians [notzrim] and the heretics [minim] perish in a moment, let them be blotted out of the book of the living.”  While there is some debate about how early the curse is and what exactly is included, something like it seems to be early since Justin Martyr says the Jews curse those who believe in Christ in their synagogues. 
Finally, one sees this separation in Roman perceptions. Christians are a new superstition. Pliny the Younger asks Trajan about what to do with Christians. As Carleton Paget says, “Prima facie, then, such evidence would appear to show that to some outsiders, Christians had an identity separate from that associated with Jews, and precisely because this is the view of those looking in from the outside, it should be taken seriously.” 
So, the early Christians were ethnically mixed. While the exact mix is debated, this mix is clearly important. It would lead to the issue that become popular and debated in the second century, like Gnosticism.
We must also consider the socio-economic situation. Meeks argued quite a while ago that Pauline churches represented a cross-section of typical society. Pliny said Christians were in all ranks of society. There were clearly lower classes like slaves, as seen references by Pliny, Ignatius, and others. By the end of the second century, Tertullian and Minucius Felix say Christians are from all classes. This is confirmed by Justin Martyr, the Shepherd of Hermas, and more. Irenaeus mentions believers in the royal palace. This explains why Clement of Alexandria would defend the right of Christians to have wealthy by the end of the second century. Christians believed they should use this wealth to help the poor, which is borne out by the evidence.
But were the Christians in the second century dumb? Celsus sure thinks so. Literacy is a spectrum, and the majority of people back in the second century would not be literate in the way we think today. Christianity in the second century did, however, include educated persons. One sees in the writings that come from this period, only some of which have been mentioned. Justin Martyr stands as a great example of a Christian who is clearly educated. Galen in the middle of the second century sees Christianity as a philosophy that is not inferior to pagan philosophies.
Male and Female
As to sex, a close reading of the New Testament shows how profile people among both males and females. This continued on in the second century. While the men are often well known from writing books, women played a prominent role too. One can find various references to notable women in early Christian writings. Celsus goes as far to say that Christians only convert the dregs of society, which includes women in his view. Sociological studies by Stark and Lampe suggest that most primary conversions were by women, especially among the higher class.
To summarize it all, Kruger says, “Paul’s vision of Christianity as something intended for all people–Jew and Greek, slave and free, male and female–was on its way to being realized in the second century.” 
Political and Intellectual Responses
Here we will look into how outsiders responded politically and intellectually to Christians. While some of this floats around in popular circles, it is generally a less contentious area among laypeople than other areas. Therefore, this section will be shorter.
Oftentimes Christians have seen the early centuries of Christianity as including widespread, systematic, and official government persecution. Others have rightly pushed back against this. While there was no official government action to persecute Christians across the whole empire, this does not mean we should swing in the opposite direction by denying any and all persecution. Let’s look at some of the evidence.
As mentioned before and in a fairly well known piece of evidence, Pliny the Younger writes to Trajan about what to do with Christians. Like apparently many at the time, Pliny feared that Christians were engaged in all sorts of wrongful activity in their meetings. He thus interrogates them to get to the truth of the matter. While he finds that they eat normal food, aren’t engaged in sexual immorality, and more, he believes Christianity is a superstitio, something “strange, foreign, or subversive.”  Christianity was out of step with what Romans thought about religion. In fact, two other historians believe the same thing: Tacitus (about 116) and Suetonius (about 120).
Christianity was out of step because Christians were devoted to only the true God. While they might not commit a crime, this undermining of traditional Roman religion and practice toward the emperor was enough. People were more than willing to give the names of Christians. Pliny thus forces them to recant or face death. The martyrdom of Ignatius, Polycarp, and, if you’re paying attention to names, Justin Martyr confirm this picture.
Eusebius records a letter written about persecution in Gaul. Again, accusations of cannibalism and sexual immorality are present. However, a number of people are recorded as being tortured and being put to death for bearing the name “Christian.” Kruger lists, “Vettius (a lawyer), Sanctus (a deacon), Pothinus (a 90-year-old man), Maturus (a new convert), Attalus (a Pergamene by race), Ponticus (a 15-year-old boy), and Blandina (a slave woman).”  Ireaneus further confirms persecution and martyrdom.
In northern Africa, the Acts of the Scillitan Martyrs mentions the trial of 12 Christians before authorities in Carthage around the end of the second century. Kruger notes that some doubt this account but most scholars find it generally reliable. Again, further confirmation is found in the northern African church leader Tertullian. These Christians must face the sword because they are Christians.
To summarize, while persecution was not based on an official decree or as widespread and perpetual as some have imagined, persecution of Christians for being Christians was not uncommon and could be severe.
Kruger then surveys a number of thinkers who criticized Christianity: Lucian of Samosata, Galen, Fronto, and Celsus. The intellectual climate was hostile toward Christianity. As Kruger says, not only did they criticize some of the sociological aspects mentioned above, “the philosophers and rhetoricians of the second century struggled to understand and appreciate core Christian doctrines, expressed frustration at Christianity’s anti-social disposition, and regarded the Christian claims as lacking in historical evidence or empirical demonstration.”  The Christian apologists played an important role in undermining both the false charges (sexual immorality and cannibalism, to give two examples) and bolstering the Christian faith. Here Kruger lists Quadratus and Aristides, the Epistle to Diognetus, Justin Martyr, Tatian, Athenagoras, Theophilus, and Tertullian.
Ecclesiology is the study of the church. Here Kruger turns his attention to a plurality of issues as to what Christianity in the second century looked like. We will run through these briefly since a lot of them are well known.
Kruger believes the New Testament church had a plurality of elders/bishops (where elder is taken in the New Testament sense of the term and elders and bishops are functionally one and the same office). There was not, however, a single monarchial bishop. He thinks this both stayed true in the second century and didn’t. While there are limitations to the earliest evidence, he points to the Didache, 1 Clement, the Shepherd of Hermas, and Polycarp as showing this plurality model. Even though this evidence is limited, he writes, “there is no positive evidence for the existence of a singular bishop in these earliest stages of the church.” 
There is evidence, though, of this development into a single bishop model. Ignatius plays a key role here. He refers to bishops. More than that, he refers to a singular bishop. While there is considerable debate as to whether Ignatius is inventing this idea or it is already normative, the evidence does seem to favor the normative view since Ignatius refers to bishops in the five Asian congregations he addresses. What is noteworthy, though, is that while writing to Rome he never names or refers to a singular bishop there. At this point, then, there seems to be diversity in the structure of church leadership in Christianity. Also, there is no evidence that the bishop is over the presbytery; he appears to be a leader who has been singled out because of his gifting.
This development clearly did occur, though. In the latter half of the second century, Hegesippus draws up a list of the bishops of Rome going back to Anicetus. Hegesippus’ influenced Irenaeus and others. While Irenaeus’ high view of the office of bishop is undoubted, Kruger notes that Irenaeus sees “the office of bishop is, in some sense, an extension of the office of presbyter.”  By the end of the second century, this transition has certainly taken place. Kruger cites the Apostolic Tradition attributed to Hippolytus in the early third century as an example.
Christianity from the beginning met in house churches. One finds confirmation of this extending into the second century in Celsus’ criticism of Christians’ private meeting, the Shepherd, Irenaeus, the Acts of Justin and His Companions, and apocryphal works like the Acts of Paul, the Acts of Peter, and the Acts of John.
Two important qualifications are in order though. First, there is some evidence that Christians began to modify their homes to make them more accommodating for this style of meeting. Second, one should not think along the lines of single-family dwellings since neighborhoods for members of other types of organizations existed and would be a good model for how Christians patterned their meetings. None of this entails that Christians never met outside of a home, for they certainly did.
Already in the New Testament there are connections between churches. Paul uses the singular for church at Corinth, Cenchrae, and Thessalonica. 1 Clement also uses the singular for the church at Rome and also for Corinth. Polycarp refers to the singular church At Philippi. On the other hand, when Justin is being interrogated he only mentions his local church at Rome and says he does not know of others. What his precise meaning is, though, is a bit unclear since he would almost certainly actually know of others. So possibly he meant something beyond propositional knowledge of the existence of other churches in Rome. This does indicate, though, that the connections between churches might not have been uniform. You can further see connectivity by the debate over the proper date to celebrate Easter.
Kruger argues that it was the worship practices of early Christianity that set it apart from both the Greco-Roman world and the Jewish world. As noted above, Christian worship was exclusive: Christians worshipped the one true God and no other. Their worship of the one true God was the God of Israel. More than that, they worshipped Jesus as God. We saw this above when we discussed Pliny the Younger. Numerous sources offer doxologies or hymns to Jesus. Kruger mentions 1 Clement 20.12; 50.7; Ignatius Ephesians 2.2; 4.1-2; etc.  Lucian mocks Christians for “worshipping that crucified sophist.” 
The elements of Christian worship should be well known. They gathered together primarily on Sunday. Their gatherings included teaching both from the Old and New testaments. They ate together, including partaking of the Lord’s Supper. And baptism was clearly a part of Christianity. Finally, you have standard elements like singing, praying, and more.
Diversity in Christianity
Above I mentioned that often there are conspiracies about second-century Christianity. These conspiracies tend to swirl around alternative groups and claimed political conniving of orthodox Christians. Reconstructing these groups can be difficult because our information often comes from opponents of these groups. Nonetheless, let’s briefly sample some of these groups in order to understand the landscape.
The Ebionites said that you must observe the Mosaic Law in order to be saved. According to some, they also repudiated Paul’s letters. They further believed Jesus was a mere man who was adopted by God as His son and thus was not born of a virgin.
The Marcionites contrasted the God of the Old Testament with the God of the New Testament. The God of the Old Testament was demand centered and wrathful. The God of the New Testament showed mercy and love. Thus, the God who sent Jesus is not the God of Israel. There is some debate here whether Marcion or his followers believed the Creator was an evil or good God. Either way, this movement ended up rejecting the creator as evil and also said that Jesus was not human, but only appeared. Marcion himself is famous for accepting an edited version of some of Paul’s letters and Luke’s gospel.
The Gnostics are a notoriously hard group to pin down, trace their origins, and understand the contributing streams. This movement largely emphasized a distinction between the physical and spiritual. The physical was the creation of a demiurge, a evil creator god. Jesus only appeared to be physical. Salvation came through secret knowledge that Jesus supposedly passed on to secret individuals. They would often use the same/similar language of orthodox Christians but mean quite different things.
The Montanists are a final group. Even Tertullian would later adopt some of their beliefs. They are known for prophetic utterances, ecstatic experiences, and an apocalyptic fervor. They did, however, hold orthodox views of God, Jesus, creation, and the church.
With all of these diverse groups, what does this mean about Christianity in the second century? Was there simply a bunch of different Christian groups with no group actually representing authentic Christianity? This has been the argument of some. We turn there next.
Unity in Christianity
To reiterate, some take the diversity to entail that there was no real and true Christianity. Instead, there were a bunch of competing forms. By historical accident, what we know as orthodox Christianity ended up winning out. However, orthodox Christianity had no real claim to the title of “Christianity” over the other groups mentioned above. Walter Bauer proposed this view long ago. While there was great diversity (as discussed above), there was also great unity. Let’s look at some examples.
The Rule of Faith
The rule of faith is a summary of what orthodox Christians believed about what the apostles taught. It is a sort of tradition, but one that Christians believed they only preserved and passed along. Interestingly, it is found all over the place: Dionysius of Corinth, Hippolytus, Irenaeus, Clement of Alexandria, Tertullian, and Origen. Its function was as a summary of the biblical storyline. Kruger notes that the rule is found amongst diverse figures (Irenaeus, Tertullian, Origen, etc.), different geographical areas (Rome, North Africa, Gaul, Syria, etc.), and various genres (apology, letter, acts, etc.).
Kruger summarizes the rule as a history of redemption. He says it has seven theological themes: “(1) there is one God, the creator of heaven and earth; (2) this same God spoke through the prophets of the Old Testament regarding the coming Messiah; (3) Jesus is the Son of God, born from the seed of David, through the virgin Mary; (4) Jesus is the creator of all things, who came into the world, God in the flesh; (5) Jesus came to bring salvation and redemption for those who believe in him; (6) Jesus physically suffered and was crucified under Pontius Pilate, raised bodily from the dead, and exalted to the right hand of God the Father; and (7) Jesus will return again to judge the world.” 
It should come as no surprise that Christians expressed their views as the retelling of the biblical story. Their faith was not merely one of propositional affirmations but about the God who was consistently at work in the world, from creation until the end. Finally, notice that when you look at this summary of the rule of faith you can clearly see all of the heresies that are ruled out. The affirmation that God is the creator and is the same God of the Old Testament clearly rules out early heresies like Marcionism and Gnositicism. Similarly, the emphasis on Jesus as God, born of the virgin, and the redeemer strikes against Ebionitism. So, the wide dispersal and early affirmation of the rule speaks strongly in favor of orthodox Christianity.
One of Bauer’s arguments is that “heresy” often spread to geographical areas before “orthodoxy” did. By engaging in serious historiographical work, he argued for this thesis. This is certainly a point worthy of consideration. While it is not obvious how anything substantive would follow, one should still commend Bauer for raising and discussing the issue. Nonetheless, his argument is weak at various points.
First, notice that the leadership in the early church is largely orthodox Christians. Many of these names have been mentioned and more could be multiplied. Also observe that these orthodox Christians come from a diverse geographical area, just like the rule of faith.
This does not mean that there were no leaders from heretical groups, but the contrast is stark. Kruger also points out that there is no evidence that the heretical leaders held the office of bishop in their various locales. To wit, “Of course, we have scattered hints here and there that ‘heretics’ were influential, but there is no explicit mention, at least in the second century, of any identifiable gnostic, Marcionite or Ebionite holding the office of bishop.”  He notes that we do have hints that Valentinus may have been considered for the office of bishop of Rome, but that report is in doubt. 
Florinus could be another example but there is no evidence that he served as a bishop. His questionable theology was also a development. Eusebius mentions a Marcionite presbyter named Metrodorus. Eusebius, however, claims that he was martyred with Polycarp while other sources indicate that he was martyred with Pionius more than a century later. Another example is Zephyrinus, but his form of heresy was modalism, not the sort being surveyed here. Hippolytus mentions that heretical followers of Marcus may have had a sympathetic bishop. Kruger notes that this seems to be a reference to the Marcosians in his own days (early third century). Finally, Natalius is from the third century.
Even if one of these were an exception, that simply proves how prevalent orthodox bishops were. All of this is further confirmed by Ignatius telling his readers to obey their bishops and presbyters, something he would not say if they were overrun with heretics.
Kruger next looks at the geographical question. He cites a number of studies that undermine Bauer’s claims. Let’s take one example at random: Asia Minor, Corinth being an interesting example. Bauer claims that since 1 Clement talks about ousting church leadership then this is evidence of a gnosticizing takeover. One problem: 1 Clement mentions nothing about any gnostic threat. On top of that, Hegesippus points at second century Corinth as a example of staying true to the faith. Overall, Bauer’s claims are exaggerated. The evidence simply isn’t there.
One finds further confirmation about the dominance of orthodoxy in Christian literature from the time. As is well known, orthodox writings dominate the period. Even in Egypt, an area where one would expect heretical literature to dominate if heresy was prominent, the evidence favors the orthodox writings. Now, one can certainly say that this is because somehow the orthodox stamped out and destroyed all of this literature. Even if we had good reason to believe that, all that shows is that this argument does not work in favor of orthodoxy. That response does nothing to buttress the profile of heresy in the second century.
In a wonderful quote by Thomas Robinson, the argument in favor of widespread heresy based on orthodox rhetoric is undermined: “The number of heretics has no proportional relationship to the decibel of the polemic raised against it.”  In fact, observing the rhetoric of writers at the time seems to point in the orthodox direction. Clement of Alexandria records excerpts of the Valentinian Theodotus where he says many are material, not many are psychic, and few are spiritual. Celsus’ discussion about his travel places him in eastern areas like Phoenicia and Palestine. So, there is no reason to think he only knew Roman Christianity. With that in mind, notice that Celsus (1) sees the fracturing of Christianity as a later development, (2) sees the multitude as orthodox Christians, and (3) contrasts those who do not believe in the Jewish creator God with the “Great Church.”
Back to the First Century
To summarize briefly, when one compares the seven tenets of the rule of faith listed above with the New Testament writings there is a clear compatibility. If one wants to go deeper by arguing that there was no true Christianity in the first century, then there are still problems. First, even a minimialistic core of first century Christianity fits better with orthodoxy than with the heretical groups. Second, the connections between the early churches, Paul, and the apostles clearly favor an outline like the rule of faith.
Overall, then, the argument for heresy being just as early as orthodoxy is simply wanting. Orthodoxy is too rooted, too prominent, too widespread, and too diverse for this argument to hold up. There certainly was orthodoxy and heresy in second century Christianity.
A Textual Culture
Orality and Textuality
Books mattered to the early Christians. If that is not obvious, I would simply point you to the Bible. Beyond that, we have mentioned a number of authors and works by early Christians. As discussed in the section on how the church worshipped, there was an oral aspect to Christian culture. They heard God’s word read aloud. One interesting anecdote comes a bit after our period. In a letter to Jerome, Augustine recounts how he used Jerome’s Latin translation one Sunday in church and the assembly almost rioted when they noticed one word was wrong. 
As should be obvious, none of that entails that Christians looked down upon written works. Again, their Scriptures were written. Their leaders wrote books. Both orality and textuality mattered. As Kruger notes, “orality and textuality existed in a complex, symbiotic relationship.” 
Book production also mattered to Christians in the second century. The development of the codex and the canon seem to be intertwined. The codex was a bunch of folded papyrus/parchment that were bound at the spine. Essentially, it’s an ancient form of book. In contrast to the culture around them, the early Christians loved this form. Since the codex would make sense as a result of canon consciousness, the fact that the prominence of the codex is already there in the second century speaks in favor of an early canonizing process.
A number of features are interesting here. First, the scribal hand of early manuscripts like P. Oxy. 405, P46, P4-64-67, and more is highly regarded. While the Christian scribes might not have been copyists in the commercial book trade (although maybe some were), they were very capable “multifunctional” scribes, trained professionals who may be best suited for a private context.  Second, there is the nomina sacra, scribal abbreviations for words like God, Jesus, and more. The presence is so dominant that it is hard to find manuscripts without it. Clearly Christians cared about their books and their contents. They were making developments within book culture after all.
Third, there are reader’s aids in early manuscripts. This includes more punctuation, less lines per page, spaces to mark sense-units, and more. The goal was to make reading easier. All of this means that Christians cared to preserve the text. The use was often for public reading. More than that, some of these developments show that Christians wished to widely disseminate their Scriptures. Christianity in the second century was both able and eager to preserve their Scriptural text.
A Stable Text
Christians also had the interconnectedness and ability to carry out this scribal transmission. We therefore have good reasons to hold to the stability of the early text. On top of that, consider the following reasons. First, early Christians believed the (now) New Testament books they were copying to be Scripture (more on this below). Second, even within the second century Christians were quoting Deuteronomy about not adding or taking away from books when transmitting texts. Third, even second century manuscripts include corrections. Finally, if there were radical fluidity in the second century then we would expect this to show up in our later manuscripts; it doesn’t. There simply is no good reason to believe in radical fluidity in the earliest manuscripts. More than that, we have good reasons to believe the earliest text was stable.
Above we noted the early development of the codex. This shows an early development of canon consciousness: some books were Scripture while others were not. We will now look at that issue in more depth.
Part of the difficulty is defining canon. If by that we mean a definitive list including every work that is nearly universally agreed upon, then we are investigating one question. However, if we take books being used as an authoritative norm in Christian communities as showing canon consciousness, then we have a different question on our hands. Let’s look at this latter option: books being used as an authoritative norm in Christian communities.
Setting the Stage
Recall again our discussion of the rule of faith. This captured the overarching storyline of the bible. It also developed very early. The rule of faith is an example of canon consciousness. If the storyline of God’s action in history is to be summarized then you probably need to know how God has acted in history. Given that the early Christians knew this by turning to authoritative books, we would expect them to have the same framework while evaluating books surrounding the rise of Christianity.
Maybe the most prominent second century figure in this discussion is Irenaeus. He affirms the scriptural status of all four gospels, Acts, the Pauline epistles (minus Philemon), Hebrews, James, 1 Peter, 1 and 2 John, and Revelation. If you’re keeping track, that is 23 out of 27 New Testament books. However, it is incorrect to see him as inventing the canon. His use of Scripture is natural and without apology. Moreover, as we will see, it is historically inaccurate to say that he is the only second century Christian who is interested in questions of canon.
Another indicator is the well-known Muratorian Fragment. It includes nearly the same list as Irenaeus (the difference is 1 Peter). The Fragment declares some books in and others out. It suggest a mature reflection on the canon. Theophilus of Antioch is another witness in the latter half of the second century. His canon is also close to Irenaeus and the Fragment. Finally, Clement of Alexandria writes at the end of the second century. He adds to Irenaeus’ list by including Jude. But what about earlier?
Going Further Back
Given the widespread canonical consciousness noted above, it seems likely that it has some roots earlier. There is good reason to believe Justin knew all four gospels (he mentions gospels by apostles and their followers, he cites all three Synoptics, he shows familiarity with the Logos theme in John, and his disciple Tatian clearly knew and valued all four). Further, since Justin notes they are read and expounded in worship shows that they acted authoritatively for the Christian congregations. He clearly knew Revelation, but the Pauline letters is more opaque.
The canon of Marcion is well known. But notice that Irenaeus says Marcion shortened an already existing list. This is the conclusion of a number of scholars and seems to be the general tide. One possible clue is found by reconstructing Marcion’s Luke text and noting that it has harmonizing tendencies from Matthew and Mark. This suggests a circulation together that influenced Marcion. In fact, even Harnack affirmed that the fourfold gospel predated and influenced Marcion.
Aristides advised Emperor Hadrian in 125 to read the gospel. But for Aristides this did not mean only one gospel. He clearly knew Luke and John, while Matthew and Mark are possibilities. He says that these works have power, a likely reference to the Spirit. Finally, he mentions other writings, which, based on echoes, likely includes Paul’s letters and maybe Peter’s too.
Other early writings bear witness to this movement. The early Epistle of Barnabas seems to be citing Matthew 22:14, with the common scriptural formula “as it is written.” Ignatius in writing to the Ephesians references a Pauline letter collection. He clearly had a high view of the apostolic office and Paul. Finally, there is also good evidence that he also knew works from Matthew, Luke, John, and Peter.
Polycarp also seems to know of a Pauline collection. His high view of the apostolic office lends credence to treating these writings as authoritative. He also cites Ephesians with the phrase “as it is written in these Scriptures.” He also knew 1 Peter and 1 John. There is also good reason to believe he knew Matthew and John. Finally, 1 Clement also knows of a Pauline letter collection. He has a high view of Paul’s apostolic office and even says that Paul wrote his letters “in the Spirit.”
Finally, there is Papias. He was friends with Polycarp and a hearer of the apostle John. He draws on even earlier tradition for his points. His testimony shows that both Matthew and Mark were known by name by the end of the first century. He also states that these gospels had apostolic connections. The reason for doing this seems to be to highlight their unique authority. He says that Mark determined to leave nothing out of what he heard and to include no falsehood. He sees the gospels as historically reliable and authoritative. Since Papias knew 1 John and Revelation and sat on John’s teaching, it’s likely he knew the gospel of John. He also seems to cite Luke 10:18. Others have argued that he knew 1 and 2 Corinthians.
There is good reason then to believe canon consciousness happened early. It certainly happened near the end of the second century. These multiple lines of evidence show that it happened even earlier. Moreover, it is important to get the relation of authority and orthodoxy/heresy right. As Kruger says, “Thus it appears the existence of the New Testament canon is not the result of debates over orthodoxy and heresy, but the very thing that allowed the Church to survive in the midst of those debates.” 
Hopefully this long review dispelled a number of myths. Christianity in the second century was hugely important for the development of Christianity. Getting this century right is important. Any engagement with pop culture also shows that this discussion is important to apologists. Kruger’s Christianity at the Crossroads is a wonderful and accessible entry into the topic.
Notes Michael Kruger, Christianity at the Crossroads, 14-15.
 Ibid., 21; citing S. T. Katz. I hope it is clear that this section is not downplaying Christians involvement in hostilities. The reason why I passed over that quickly is because it is well known and I desire to keep this brief.
 Kruger cites Justin’s Dialogue 16.4 and says to cross reference 96.2.
 Cited on ibid., 22.
 Ibid., 39; emphasis original.
 Ibid., 42.
 Ibid., 51.
 Ibid., 61.
 Ibid., 80; emphasis original.
 Ibid., 84.
 See footnotes 96 and 97 on ibid., 96.
 Ibid., 97.
 Ibid., 144.
 Ibid., 147.
 Ibid.; emphasis original. See the following discussion in the book for the information that follows in the main text.
 Cited in ibid., 153.
 Ibid., 171.
 Ibid., 174.
 Ibid., 191.
 Ibid., 226.