My dissertation addresses two related questions about the soldier of the Roman Republic: how writers who treated the Republic interpreted the figure of the soldier, and what that soldier’s real experience was like. The dissertation shows how the soldier figure was wound into the overall objectives of the writers Polybius, Livy, and Sallust, who made the figure of the Roman soldier essential to their conceptions of Roman national character, and used the soldier to demonstrate their perceptions of the ascension, stability, and then decline of Roman society. I conclude that the soldier figure has a privileged role to play in Roman self-identity and representation. I then address how we can access the soldier’s real experience, and use the Bellum Hispaniense, the work of a low ranking soldier, to demonstrate that the soldier’s major concern is for information. Success in warfare and the cohesion of an army depend on the soldier’s mentality, rather than his physical body. I explore this by creating a methodology for interdisciplinary research involving modern history and psychology. I argue that unusual or seemingly incongruous incidents, instead of being labeled as romantic or legendary discourse, can be usefully reframed in terms of the study of human behavior. I show similarities between recorded behaviors of Roman soldiers and documented cases of modern soldiers who have developed dependency on their leaders. I also address the Roman army more broadly, and argue that the rules and regulations in the Roman army bear strong resemblances to those employed in the German Wehrmacht and the Iraqi army to encourage “victory or death” style soldiering. I conclude that this historiographical trope was deliberately enforced using psychologically manipulative methods.