In the latter part of Verse 10 and in Verse 11, Paul mentions two groups, both involving Christians and, maybe some non-Christians, as well:
Greet those who belong to the household of Aristobulus. Greet Herodion, my relative. Greet those in the household of Narcissus who are in the Lord. (Romans 16:10b-11)
Dr. William Barclay, who was one of the best commentator of all when it came to finding the background of Biblical stories, tells us that Aristobulus may have been the grandson of King Herod the Great, who lived in Rome. He was behind the scenes politically, but was the close friend of the Emperor Claudius. When Aristobulus died, his household, i.e., his servants and slaves, became the property of the emperor (and by this time Nero was on the throne, succeeding Claudius, who had been murdered), but his household was still known as the household of Aristobulus. It is believed that this is the group Paul was referring to. If this is true, then it is safe to presume that even in the royal household there were a number of Christian servants and slaves who exercised great influence on the leaders of Rome—even the emperor himself. One of the supporting facts to this, is that Paul mentions his relative, Herodion, in connection with these servants. The scholars get this from his name. It is believed that he had connections with the family of Herod. It also makes them think that Paul himself had some connection with the ruling family of the Jews. His relative, Herodion, had become a Christian, and was living in Rome as part of the household of either Aristobulus or Narcissus.
In Roman history, the most famous Narcissus known was a former slave who became the personal secretary of the Emperor Claudius. He was pretty wealthy, because he was in charge of the correspondence of the emperor. (His palm had to be greased before a letter got through to the emperor.) When Claudius was murdered, Nero took over, and he also took over the household of Narcissus. Not too long after Nero came to the throne, he forced Narcissus to commit “suicide,” (I say that cautiously) as he did many men. But the fact that he is mentioned in Paul’s letter, it appears that there were Christians within the emperor’s household. See, Paul wrote, “Greet those in the household of Narcissus who are in the Lord.” What I am getting at is that in the heart of the Roman Empire, there was already a Christian witness established, and that Paul sends greetings to the slaves and servants in the house of Nero. That may not mean much to you, but I find it rather significant.