Paul was a radical Jew, present for the stoning of Stephen, part of active church persecution.
Paul was stopped by God on his way to Damascus and became a Christian.
He spent some time in Damascus, then fled after a plot on his life (Acts 9:23-25).
Then he came to Jerusalem briefly, where there was a plot on his life (Acts 9:29,30).
So he was sent to Tarsus, eventually ending up in Antioch.
First Missionary Journey:
While in Antioch, the Holy Spirit said, "Set apart for me Paul and Barnabus" -
Acts 13:1 - 15:35 tells the story (excepting the Jerusalem Council in Acts 15) of the resulting journey,
which we call the first missionary journey.
It sees the spread of the Gospel throughout Asia Minor (Turkey), and Paul's increasing fruit among the Gentiles.