To whom did Paul write the first and second epistles to the Thessalonians?
Christianity came to Thessalonica through Paul, Timothy, and Silas during Paul's second missionary journey. Paul and his companions had spent only three weeks in Thessalonica, but according to the accounts of Acts and Thessalonians, their ministry had been characterized by enormous success. In this short amount of time, Paul had not only established this new church, but he had built a strong foundation of faith in the lives of these new believers. This was certainly an extraordinary occurrence not typical of gospel ministry to the pagan gentile world. We learn from Acts that some of the Jews were convinced and followed Paul, but many of the new converts to whom he wrote were Greeks and "leading women."
Paul hadn't been gone from them long when he made time for his first letter to the Thessalonians. Paul had stirred up a lot of opposition in Thessalonica among the Jewish radicals and those who were loyal to Caesar. A band of these radicals formed a mob and created an uproar in the city over Paul's intrusion. They went to the home of some of the brethren looking for him, and when they saw that he was no longer there they persecuted those who associated with Paul. The opposition accused Paul of treason for proclaiming a king other than Caesar, namely Jesus. After being gone for just a short time, Paul sent Timothy back to encourage the Thessalonians in their faith and to report to him regarding their circumstance.
Paul seemed to be concerned after having left them in such a hostile environment, but he found great comfort in Timothy's positive report. However, Timothy pointed out that they had a drastic misconception of the Lord's return. Paul wrote the first letter in an attempt to assure them that Christ was certainly coming again, and Paul wrote the second letter instructing them how they ought to live in the until the day of Christ's return.