Defeat of Rome in the East: Crassus, the Parthians, and the Disastrous Battle of Carrhae, 53 BCDuring the last stages of the Republic, Rome suffered its greatest military disaster since Hannibals invasion of Italy over 150 years earlier, though this defeat had more far reaching consequences. While Rome was able to recover from its disaster at Cannae, it never did retrieve the results of Carrhae, a defeat that sealed the East as an impenetrable barrier to Roman ambition, and also signaled the demise of the Republic. In 53 BC, Marcus Crassus, the