Sosthenes
Sosthenes (meaning: safe in strength or savior of his nation) appears twice in the New Testament. (1) The chief ruler of the synagogue at Corinth who was seized and beaten by the crowd before the proconsul Gallio when Gallio refused to adjudicate the Jewish complaint against Paul (Acts 18:12–17). Whether his attackers were Jews enraged at his failure or Greeks expressing anti-Jewish sentiment is debated. (2) A Christian named Sosthenes is co-sender of Paul's first letter to Corinth (1 Cor. 1:1), described as "the brother." Many scholars identify these as the same person — the synagogue leader who, after the beating, came to faith and became a co-worker of Paul.
If the identification is correct, Sosthenes represents a remarkable conversion: the very man whose role as synagogue ruler set the scene for Paul's opposition in Corinth became his associate in the letter to the church founded there.