Titus Livius (Livy), The History of Rome, Book 21
D. Spillan, A.M., M.D., Cyrus Evans, Ed.

26. When the account of this sudden disturbance was brought to Rome, and the senators heard that the Punic had also been increased by a Gallic war, [2??] they order Caius Atilius, the praetor, to carry assistance to Manlius with one Roman legion and five thousand of the allies, enrolled in the late levy by the consul: who, without any contest, for the enemy had retired through fear, arrived at Tanetum. [3] At the same time Publius Cornelius, a new legion having been levied in the room of that which was sent with the praetor, setting out from the city with sixty ships of war, by the coast of Etruria and Liguria, and then the mountains of the Salyes, arrived [4??] at Marseilles, and pitched his camp at the nearest mouth of the Rhone, (for the stream flows down to the sea divided into several channels,) scarcely as yet well believing that Hannibal had crossed the Pyrenaean mountains; [5] whom when he ascertained to be also meditating the passage of the Rhone, uncertain in what place he might meet him, his soldiers not yet being sufficiently recovered from the tossing of the sea, he sends forward, in the mean time, three hundred chosen horses, with Massilian guides and Gallic auxiliaries, to explore all the country, and observe the enemy from a safe distance. [6] Hannibal, the other states being pacified by fear or bribes, had now come into the territory of the Volcae, a powerful nation. They, indeed, dwell on both sides of the Rhone: but doubting that the Carthaginian could be driven from the hither bank, in order that they might have the river as a defence, having transported almost all their effects across the Rhone, occupied in arms the farther bank of the river. [7] Hannibal, by means of presents, persuades the other inhabitants of the river-side, and some even of the Volcae themselves, whom their homes had detained, to collect from every quarter and build ships; and [p. 725]they at the same time themselves desired that the army should be transported, and their country relieved, as soon as possible, from the vast multitude of men that burthened it. [8] A great number, therefore, of ships and boats rudely formed for the neighbouring passages, were collected together; and the Gauls, first beginning the plan, hollowed out some new ones from single trees; [9] and then the soldiers themselves, at once induced by the plenty of materials and the easiness of the work, hastily formed shapeless hulks, in which they could transport themselves and their baggage, caring about nothing else, provided they could float and contain their burthen.