How Roman Army Won Against Arabs in Italian Peninsula

Not the Rome of the Ancient Roman Empire. Scenario: The Roman army had marched into the Italian peninsula expecting to meet a small force of rebels, and had not prepared for such a large force of 5000 Arab attackers. The Romans were outnumbered and outmaneuvered, and the battle was quickly won by the Arabs. In the aftermath of the battle, the Romans regrouped and decided to retreat from the Italian peninsula and retreat back to Rome itself. The Arabs, satisfied with their victory, decided not to pursue the Romans and instead decided to retreat out of the Italian peninsula and back to their homeland. The Romans were left in peace, albeit weakened from the battle, and the City of Rome was safe from invasion.