In the mid-1st century BC, despite his military victories elsewhere, the Roman Empire faced a rival power in the east: the Parthian Empire. The first war between two superpowers of the ancient world resulted in the complete defeat of Rome and the death of Marcus Crassus. When Rome collapsed into civil war in the 40s BC, the Parthians seized the opportunity to invade and conquer the Middle East, pushing Rome back to Europe. Two decades of war followed with victories and defeats on both sides. The Romans finally managed to win a victory against the Parthians, thanks to the great, but now neglected, general Pompeius Ventidius. These victories served as a stepping stone for Mark Antony's plans to conquer the Parthian Empire, which ended in a humiliating defeat. Gareth Sampson analyzes the military campaigns and various battles between the two superpowers of the ancient world and the war that defined the shape and distribution of the Middle East for the next 650 years.