C. Julius Caesar, Gallic War

Among the Helvetii, Orgetorix was by far the most distinguished and wealthy. He, when Marcus Messala and Marcus Piso were consuls [61 B.C.], incited by lust of sovereignty, formed a conspiracy among the nobility, and persuaded the people to go forth from their territories with all their possessions, [saying] that it would be very easy, since they excelled all in valor, to acquire the supremacy of the whole of Gaul. To this he the more easily persuaded them, because the Helvetii, are confined on every side by the nature of their situation; on one side by the Rhine , a very broad and deep river, which separates the Helvetian territory from the Germans; on a second side by the Jura , a very high mountain, which is [situated] between the Sequani and the Helvetii; on a third by the Lake of Geneva, and by the river Rhone, which separates our Province from the Helvetii. From these circumstances it resulted, that they could range less widely, and could less easily make war upon their neighbors; for which reason men fond of war [as they were] were affected with great regret. They thought, that considering the extent of their population, and their renown for warfare and bravery, they had but narrow limits, although they extended in length 240, and in breadth 180 [Roman] miles.