Jerusalem Council: There was a dispute over the status of Gentile Christians. Some Judaizers believed and taught that Gentile believers must come into the Christian church under the same terms as Gentiles came into Judaism. "Some men came down from Judea to Antioch and were teaching the brothers: 'Unless you are circumcised, according to the custom taught by Moses, you cannot be saved'." (NIV) Acts 15:1
A second issue was that the Judaizers were undermining Paul's authority and teachings by proclaiming that Paul was sent by man (Peter and James in Jerusalem), not by God.
In addition, some Christian belivers in Jerusalem, who were Pharisees, also expressed their support for circumcision.
As a result the Apostles, elders, Paul and Barabas met in Jerusalem to resolve the issue of circumcision. Peter spoke saying that God makes no distinction between Jewish Christians and Gentile Christians. That Gentiles had received the Holy Spirit without being circumcised. Paul and Baranbas described the results of their work among the Gentiles. And James, stated that "we should not make it difficult for the Gentiles who are turning to God." (NIV) Acts 15:19
The result was a letter to Gentile Believers stating that Gentiles only need to conform to a few requirements that would be easy for them to follow and which would make it easier for Jewish and Gentile Christians to be in fellowship. Circumcision was not required.
The issue of Paul's apostleship was resolved in a private meeting between him and the leaders of the church. There was no doubt, Paul was an apostle.