What was the real name of the apostle who was a tax collector?

Answer 1

Another answer from our community:

Matthew also known as Levi

In the first century C.E. it was not uncommon for Jews, especially those living outside Israel or in cities having a mixed population of Jews and Gentiles, to have a Hebrew or an Aramaic name along with a Latin or Greek name. This may be why Dorcas was also called Tabitha and the Apostle Paul was also named Saul.

Answer 2

The original New Testament gospel, now known as Mark's Gospel, refers to Levi, son of Alphaeus, as a tax collector. Since the Gospels of Matthew and Luke both rely on Mark's Gospel for most of their information about the life and mission of Jesus, one would expect them to refer to this disciple by the same name, Levi, and Luke does do so in the same place. However, for some reason, Mark never again refers to Levi, but introduces Matthew as a disciple in verse 3:18 and now James as the son of Alphaeus. As the son of Alphaeus, Levi should be the brother of James, son of Alphaeus, and if Matthew was really another name for Levi, we should expect Mark to describe him as the brother of this James, just as in the same list of the apostles it describes John as the brother of James, son of Zebedee. Failure to do so suggests that Mark did not see the apostle Matthew as being the same person as Levi. Mark's Gospel is noted for containing what could be hidden clues as to its meaning, but this would only be speculation.
Matthew resolves this by never referring to Levi, speaking instead of the disciple and former tax collector as Matthew. Undoubtedly it was this and the greater emphasis on Matthew that caused the Church Fathers to attribute this gospel to him in the second century.

The authors of Matthew and Luke would seem not to have understood why Mark replaces the name Levi with the name Matthew. The answer must lie in Mark's Gospel, but it is no clearer today than it was in the late first century.

All we can say is that the name Levi was the one first used for the disciple who had been a tax collector.