Thank you for the question on Paul, “Was St. Paul really Paul, or was it a nickname like Plato?”
Saul was his birth name and Paul was his Greek name.
Saul of Tarsus lived in a Greek-Roman town. He had a Roman citizenship. Thus to maintain his status as a Roman citizen, his parents likely gave him the name Paul. However in his Jewish community, he used his Jewish name, Saul. For if Saul used his Roman name in the Jewish community, he may have been frowned upon.
For many Asians, we have a Chinese name and an American name. Although I use my American name more than my Chinese name since I lived here in the United States. For the English speaking friends, the pronunciation may be difficult for them since it is more tonal.
SUMMARY: Saul had a birth name for his Jewish lineage and a Roman name for his Greek-Roman heritage.
Your summary regarding Paul’s name is entirely non-biblical. I hope and pray children aren’t reading some of your commentary!
Paul,
What’s your take on Paul’s name?
According to The Gospel Coalition:
“There is no scriptural evidence, however, to support a name change for Saul/Paul. Here are six lines of biblical evidence that prove the popular notion wrong:
1. Jesus addresses him as “Saul, Saul” during the christophany (Acts 9:4).
Nothing in the narrative suggests Jesus subsequently changed Saul’s name. In Galatians 1:15–17, Paul speaks of being set apart before birth to preach to the Gentiles, but there is no mention of any name change.
2. Ananias addresses him as “Saul” after his conversion (Acts 9:17).
There is no mention of a name change, and he is still calling him “Saul” after the christophany.
3. The Holy Spirit calls him “Saul” before his first missionary trip.
Acts 13:2 says, “While they were worshiping the Lord and fasting, the Holy Spirit said, ‘Set apart for me Barnabas and Saul for the work to which I have called them.’” It would be odd for the third person of the Trinity to keep calling this man by his “persecutor” name if the second person of the Trinity had changed it to his “apostle” name four chapters earlier.
4. After the conversion experience, he is called “Saul” 11 more times.
Again, this would be odd if Jesus had changed his name to Paul.
5. The decisive shift from “Saul” to “Paul” in Acts happens only once Paul sets off on his missionary journeys away from Jerusalem.
This subtle shift occurs in Acts 13:13: “Now Paul and his companions set sail.” The person who “changes” his name is not Jesus, but Luke.
6. Saul and Paul were two names for the same person all along.
Acts 13:9 is the clincher: “But Saul, who was also called Paul, [was] filled with the Holy Spirit.” Here the converted person is being called both Saul and Paul—not “Saul the tyrant who was renamed Paul the Christian.” Saul and Paul are dual names of one man, both before and after his conversion.
What is your take on Paul’s name?
Paul Is Saul
As it turns out, “Saul”—derived from the famous first king of Israel, from the tribe of Benjamin, to which Saul/Paul himself belonged (Phil. 3:5)—is simply the Hebrew name for this person. “Paul”—a normal koine name—is his Greek name, derived from the Latin surname Paulus.
For someone born in Tarsus (Acts 21:39) but educated under Gamaliel in Jerusalem (Acts 22:3) in a strict form of Pharisaism (Gal. 1:14; Phil. 3:5–6), this is not unusual. Much as many immigrants to English-speaking worlds take an Anglicized name on top of their ethnic name, many Greek-speaking Jews in Paul’s day would have a Jewish/Hebrew name and a Hellenistic/Greek name.
Here’s the smoking gun: When Paul recalls his conversion, he specifically notes that Jesus was “saying to me in the Hebrew language, ‘Saul, Saul, why are you persecuting me?’” (Acts 26:14). Paul draws attention to how Jesus addressed him in his Hebrew name, and makes no mention that it is now abandoned.
When Saul/Paul launches his Gentile-focused ministry among primarily Greek-speakers (beginning with Acts 13:9), it’s natural for Luke, the author of Acts, to begin referring exclusively to him by his Greek name. Nor is it surprising that he’s later referred to as “Paul” in Jerusalem, since there were Greek speakers there too. Indeed, Luke could be making a thematic point by shifting from Saul to Paul around chapter 13, given the broader theme of Acts (e.g., 1:8). After all, the church’s nucleus is shifting from predominantly Jewish-centered Jerusalem to the Greek-centered “ends of the earth,” such as Rome.
The apostle’s two names is not unique. Several other figures in the New Testament have two given names: Joseph, later called Barnabas (Acts 4:36); Simeon, also called Niger (Acts 13:1); and Thomas, also called Didymus (John 21:2); among others.”
https://www.thegospelcoalition.org/article/no-saul-the-persecutor-did-not-become-paul-the-apostle/