ROMANS 16:22

 Q: As the book of Romans closes someone named Tertius claims to have written the letter. I have noticed before that when closing his letters Paul would often remark to the readers to notice how he had written the letter or closing remarks with his own hand. Is this a case where Paul likely dictated this letter through Tertius? What do we know about Tertius? I don’t recall hearing this name before.

This is the only place in the New Testament where Tertius' name appears. He is undoubtedly the amanuensis (and the only one of Paul's to be specifically named) who wrote the epistle at Paul's direction, with part or all of the following verses written in Paul's own hand. The ancient secretaries were generally given some freedom to arrange the author's thoughts as they pleased, with final approval by the author, of course. Thus, Tertius may have left a considerable mark on the manuscript, all under the guidance of the Holy Spirit. This could be what is implied by the alternative reading of v. 22: “I Tertius, writing this letter in the Lord, greet you.” (NRSV Study Bible)

According to later legends, Tertius became the bishop of Iconium while Quartus (see v. 23) became bishop of what is now Beirut. It was felt by some that Tertius (“the third”) and Quartus (“the fourth”) were, respectively, the third and fourth sons of the same parents. (Joseph A. Fitzmyer, Romans, pp. 749-751)

I have read somewhere, but can't locate the reference, that Tertius and Quartus were more than likely slave names. If so, then it is instructive that Paul sandwiches the name of a prominent city official, Erastus, in between those of two slaves. Early Christianity appealed to those on all rungs of the socio-economic ladder.