From what hidden sources sprang forth this new wealth of Gaul? All the documents that we possess authorise us to respond that Gaul--to begin from the time of Augustus--was able to grow rich quickly, because the events following the Roman conquest turned and disposed the general conditions of the Empire in its favour. Gaul then, as France now, was endowed with several requisites essential to its becoming a nation of great economic development: a land very fertile; a population dense for the times, intelligent, wide-awake, active; a climate that, even though it seemed to Greeks and Romans cold and foggy, was better suited to intense activity than the warm and sunny climate of the South; and finally,--a supreme advantage in ancient civilisation,--it was everywhere intersected, as by a network of canals, by navigable rivers. In ancient times transport by land was very expensive; water was the natural and economic vehicle of commerce: therefore civilisation was able to enter with commerce into the interior of continents only by way of the rivers, which, as one might say, were to a certain extent the railroads of the ancient world. To these advantageous conditions, which, being physical, existed before the Roman conquest, the conquest added some others: it broke down the political barrier that previously cut off these convenient means of penetration, the rivers; it suppressed the wars between the Gallic tribes, the privileges, the tyrannies, the tolls, the monopolies; it saved the enormous resources that were previously wasted in these constant drains; it put again the hoe, the spade, the tools of the artisan, into hands that had before been wielding the sword; and finally, it consolidated (and this was perhaps the most important effect) the jurisdiction of property. When Cæsar invaded Gaul, the great landowners still cultivated cereals and textile plants but little; they put the greater part of their fortune into cattle, exactly because in that regime of continual war and revolution lands easily kept changing proprietors. Furthermore, the more frequent contact with Rome acquainted the Gauls with Roman agriculture and its abler methods, with Latin life and its studied order. By the combination of all these causes, population and production increased rapidly. The gain in population was so considerable that the ancients themselves noticed it. Strabo (Bk. 4, ch. i, §2) observes that the Gallic women are fecund mothers and excellent nurses. With the population, wealth increased on all sides, in agriculture as in industry and in trade.