In Galatians 1:11 -2:10 Paul tells what happened to him after he first became a Christian. He ends the account by telling of a visit to Jerusalem.
Then after fourteen years I went up again to Jerusalem with Barnabas, taking Titus along with me. I went up because of a revelation and set before them (though privately before those who seemed influential) the gospel that I proclaim among the Gentiles, in order to make sure I was not running or had not run in vain.But even Titus, who was with me, was not forced to be circumcised, though he was a Greek. (Galatians 2:1-3)