How did Paul reach the pagan world and what happened when he preached to them?

Paul reached the pagan world by preaching nothing but the Gospel of the Grace of God. When he preached to those abject pagan people, they came out of their paganism and became believers, or Christians. His message is most explicitly laid out in 1 Corinthians 15:1-4.

Les explains that Paul's message was to the pagan world. He could come to abject pagan people with nothing but the Gospel of the Grace of God, and they would come out of their paganism and become believers, or as we normally say, Christians. Les also notes this was primarily God's time of calling out Gentiles from among the unbelieving world, though a Jew can be saved as well as a Gentile. The Gospel of Christ is most explicitly laid out in 1 Corinthians 15:1-4, and Paul refers to it as the Gospel of the Grace of God, the Gospel of God, My Gospel, and the Gospel according to the revelation of the mysteries.

What did Paul preach to the pagan world and what happened when he did?

Paul preached to the pagan world nothing but the Gospel of the Grace of God. When he did, abject pagan people came out of their paganism and became believers—called Christians—though that term later lost its efficacy, since today almost anyone can be called a Christian.