In 53BC the Proconsul Marcus Crassus and 36,000 of his legionaries were crushed by the Parthians at Carrhae in what is now eastern Turkey.
Crassus' defeat and death and the 20,000 casualties his army suffered were an extraordinary disaster for Rome.
The event intensified the bitter, destructive struggle for power in the Roman republic, curtailed the empire's eastward expansion and had a lasting impact on the history of the Mediterranean and the Middle East.
It was also the first clash between two of the greatest civilizations of the ancient world.
Yet this critical episode has often been neglected by writers on the period who have concentrated on the civil war between Pompey and Caesar.
Gareth Sampson, in this challenging and original study, reconstructs the Carrhae campaign in fine detail, reconsiders the policy of imperial expansion and gives a fascinating insight into the opponents the Romans confronted in the East - the Parthians.