Marcellus Gallio was a Roman official known for his role as the proconsul of Achaea during the time of the Apostle Paul. He is mentioned in the New Testament, specifically in the Book of Acts, where he presided over a trial involving Paul, who was accused of violating Jewish law. Gallio is often noted for his indifference to religious disputes, famously declaring that he would not judge matters concerning Jewish law. His tenure is significant in early Christian history, as it reflects the Roman approach to emerging religious movements and the legal status of Christianity in the Roman Empire.