And in Antioch the disciples were for the first time called Chrestianous [χρηστιανους].
So says the original hand responsible for most of the New Testament in Codex Sinaiticus at Acts 11:26, where the first Greek iota [I] in Christians [Χριστιανούς] is replaced by Greek eta [H], a much more common itacism of the second hand of this same codex but in the prophetic books of the LXX. You will observe that the attempt of the corrector of Sinaiticus to erase part of the eta (above in line four from the top) to turn it into an iota was not entirely successful.
Chrestianon and Chrestianos are used respectively in Acts 26:28 and I Peter 4:16 in Sinaiticus, and similarly undergo subsequent correction.
These three instances of the only uses of the word Christian in the New Testament are not mistakes of this original hand's eye or ear in the scriptorium which produced Sinaiticus, but instead are deliberate reproductions of evidence which it had before it, no doubt of Roman origin, which long previously had mistaken χρηστός (useful, handy, often of slaves) for Χριστός (Christ).
The Roman historian Tacitus and the biographer Suetonius in the early second century have evidence of this misunderstanding at Rome.
... quos per flagitia invisos vulgus Chrestianos appellabat. auctor nominis
eius Christus ...
... whom, hated for their shameful deeds, the commons called Chrestians. Christus, the source of this name, ...
Tacitus, Annals 15.44
The text of Tacitus implies that the Christians are Christianos from Christus, not Chrestianos from Chrestus as popularly [vulgus] misunderstood.
Suetonius, who mentions the Christiani correctly in Nero 16, in Claudius 25 nevertheless had referred to a Jewish expulsion from Rome under Claudius impulsore Chresto, at the instigation of Chrestus:
Iudaeos impulsore Chresto assidue tumultuantis Roma expulit.
He expelled from Rome the Jews constantly making disturbances at the instigation of Chrestus.
(Like Tacitus who seems quite ignorant of these details in his previous Histories, Suetonius also seems to have come up to speed by the time he composed his Nero.)
One of these Jews, Aquila, and his wife, who had been compelled to leave Rome, show up independently in Acts 18:2, connected there explicitly to the expulsion of the Jews from Rome in 49 A.D., and also to Paul the apostle of Jesus Christ.
Codex Sinaiticus' connection to Rome is highlighted by its preservation of The Shepherd of Hermas, which the Muratorian Fragment indicates was composed in Rome by the brother of Pope Pius I sometime in the second century.
