Julius Caesar was remembered in later times for the unprecedented scale of his military activity. He was also remembered for writing copiously while on campaign. Focusing on the period of Rome's war with Gaul , this paper argues that the two activities were interrelated: writing helped to facilitate the Roman conquest of the Gallic peoples. It allowed Caesar to send messages within his own theater of operations, sometimes with distinctive advantages; it helped him stay in touch with Rome, from where (...) he obtained ever more resources; and it helped him, in his Gallic War above all, to turn the story of his scattered campaigns into a coherent narrative of the subjection of a vast territory henceforward to be called “Gaul.” The place of epistolography in late Republican politics receives new analysis in the paper, with detailed discussion of the evidence of Cicero. (shrink)