Galatians 2:2 Acts 15:4
And I went up by revelation, and communicated unto them that gospel which I preach among the Gentiles, but privately [my own] to them which were of reputation, lest by any means I should run, or had run in vain.
And when they were come to Jerusalem, they were received of the church, and of the apostles and elders, and they declared all things that God had done with them.
When Paul, Barnabas, and Titus arrived in Jerusalem they met with "those of reputation": the apostles and elders. Putting the records in Galatians and Acts together we see that Paul declared two things to the leadership in Jerusalem: 1) "That gospel which I preach among the Gentiles" and 2) "All things that God had done with them."
The word "privately" is most accurately translated "one's own" or "my own." The gospel of the mystery of the grace of God was given to the Apostle Paul. Paul declared that which had been revealed to him and that he had been teaching among the Gentiles. He declared it to the apostles and elders for their consideration as leaders in the Body of Christ. Along with the gospel Paul and Barnabas presented the results of their teaching - the signs and wonders they had seen as the Gentiles had believed and received.
Galatians 2:3-5
But neither Titus, who was with me, being a Greek, was compelled to be circumcised:
And that because of false brethren unawares brought in, who came in privily to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage:
To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you.
There were at Jerusalem Judean believers who had formerly been Pharisees (doctors of the law of Moses.) These believers insisted that it was necessary to circumcise the Gentiles and command them to keep the law. Galatians declares that among these there were "false brethren unawares brought in." These false brethren were Judeans pretending to be Christian believers who had been brought in to the fellowships in Antioch and who were represented here in Jerusalem. They came in especially to influence the church to reject the gospel the grace of God. These "believers" did not influence Titus or convince him to be circumcised. Neither did the Apostle Paul subject himself to them or compromise that which he was teaching about the grace of God because of their "important positions."
As a result of these discussions regarding law and grace a formal meeting of the leadership at Jerusalem began that we call "The Jerusalem Council."
Acts 15:6
And the apostles and elders came together for to consider of this matter.
Gladly
Acts