In 1 Thessalonians 3:1-2, where were Paul and his companions left on their own when they sent Timothy?

Answer: Athens

When they could bear it no longer, they were willing to be left alone in Athens and sent Timothy to strengthen the believers.

“So when we could bear it no longer, we were willing to be left on our own in Athens. We sent Timothy, our brother and fellow worker for God in the gospel of Christ, to strengthen and encourage you in your faith,”— 1 Thessalonians 3:1-2 (BSB)