English: Caesar's construction processes for Rhine bridges in his Commentaries on the Gallic War. After he had sunk these into the river, and fixed them at the bottom, and then driven them in , not quite perpendicularly, dike a stake, but bending forward and sloping, so as to incline in the direction of the current of the river; he also placed two [other piles] opposite to these, at the distance of forty feet lower down, fastened together in the same manner, but directed against the force and current of the river.