Athenagoras is a virtually unknown apologist. He is not even mentioned in Eusebius Ecclesiastical History, which preserves more of early Christian history than any other work.
Athenagoras' A Plea for the Christians produced one of my favorite quotes and descriptions from early Christianity:
Athenagoras is not mentioned by early historians. He is mentioned by Methodius about a century after he wrote A Plea for the Christians, and he is not mentioned again until the 5th century.
His writings, however, tell us something about him, and they are impressive. Philip Schaff says that "all historians put a high estimate on Athenagoras" (History of the Church, vol. II, sec. 175). He also quotes Sir James Donaldson, a 19th-century Scottish scholar, as saying:
As far as dates go, Plea is addressed to Roman emperor Marcus Aurelius and his son Lucius, who were co-emperors from A.D. 177 - 180. This fixes the time to a very narrow window.
Though honored as eloquent and skilled in his defense of the Christian faith, he is sometimes accused of Montanist leanings because he refers to the remarriage of a widower as "a cloaked adultery." Because we know nothing about him, there is no way to know whether he wrote as a very strict Christian or whether he had actually embraced Montanism.
Athenagoras also comments that the old covenant prophets gave their prophesies in a state of ecstasy, their minds overcome, and the Spirit of God speaking through them like a flute player plays a flute. Montanists loved ecstatic prophecy, but ecstatic prophecy was not rejected by the apostolic churches, either.
We do at least know where he was from because he subscribes his Plea as Athenagoras the Athenian.
Also, despite how excellent Athenagoras' apology was, it was certainly never read by Marcus Aurelius, who acknowledges in his own writing that he had received such letters, but he simply mocks them.
Plea is remarkably easy to follow.
It begins by asking that Christians not be punished for a mere name, but on the basis of actual crimes, if any have been done.
He then lists three charges regularly made against Christians:
His answer to the first charge is perhaps the most important. Christians were called atheists because they did not believe in the pagan gods of Rome. Athenagoras refuted this by describing the Christians' belief in the one true God.
In describing their faith in God, Athenagoras clearly explains both the Trinity and the idea of a "substance" or "essence" of God, the latter being the very topic that was at the heart of the Council of Nicea a century and a half later.
Further, Athenagoras is writing to the emperor, trying to state what all Christians believe, not what some portion of them believe. He gives no indication that there was any competing view of the relationship between Father and the Son, though we know that modalism ("Jesus only") had already reared its head at that time, though with little success among Christian leaders. Theology was just not important enough to those early Christians for error to spread among leaders by means of debate.
This can be seen in the rest of the letter, which goes on to address the behavior of Christians in refuting the charges of cannablism and incest.
The common gossip about the Christians in the Roman empire was that they brought new converts to a secret meeting. There, in an elaborate ritual, they would have the new convert complete the ritual by plunging a knife into a pile of flour. The Romans said that the Christians would hide a baby in that pile of flour, which would be unknowingly killed by the new convert's knife.
The Christians would then force the new convert to be a part of eating the dead baby by threatening to turn him or her in for the murder. They would then throw pieces of the baby to dogs tied to the candle stands of the meeting hall. When the dogs went for the meat, they would overturn the lamps, plunging the hall into darkness, and rampant immorality would ensue.
This was all nonsense, of course, and Athenagoras explains that far from committing sexual immorality, Christians avoided even thinking about it. Far from killing babies, Christians would not even return blow for blow to adults.
Throughout Athenagoras marvelously turns the tables on his accusers. He shows the folly of worshiping statues and of worshiping gods that are known for the most horrendous behavior themselves. The Roman gods had committed acts that would have any Roman citizen thrown in a dungeon or put to death! Anyone familiar with Greek and Roman mythology will know that several of the gods ate their own children, and Athenagoras gives several examples of incest among the gods.
And the Romans themselves both aborted their unwanted children and left them exposed to be found and raised by strangers or to die from animals or the weather. Further, the rampant immorality in Roman society meant logically that at least some unknown incest was occurring because of promiscuity and men who didn't know they had fathered children.
Athenagoras sums this up by quoting a proverb: "The harlot reproves the chaste."
Disbelief in a physical resurrection of the dead was common in ancient Rome. Many nations believed in life after death, but not a resurrection of the physical body itself.
Thus, arguments in defense of the resurrection were common among the early Christians.
Athenagoras' defense is a notable one because he was an Athenian. In Acts 17 we learn that when Paul was Athens, he was given a hearing ... until he mentioned the resurrection of the dead, which ended the meeting at Mars Hill (v. 32).
Athenagoras the Athenian brings it back up more than a century later with a long, detailed defense of the resurrection.
Athenagoras' A Plea for the Christians is well worth reading. The apologies of the 2nd century give a clear, consistent picture of early Christianity; a Christianity that already held to those tenets which would be immortalized in the Nicene Creed and that laid great emphasis on obedience to the commands of Jesus Christ.