The sources of wealth amongst the Romans, under their later kings, were agriculture, and also, in a large proportion, foreign commerce. Agriculture, indeed, strictly speaking, could scarcely be called a source of wealth; for the portions of land assigned to each man, even if from the beginning they were as much as seven jugera, were not large enough to allow of the growth of much superfluous produce. The _ager publicus_, or undivided public land, was indeed of considerable extent, and this as being enjoyed exclusively by the patricians might have been a source of great profit. But in the earliest times it seems probable that the greatest part of this land was kept as pasture; and only the small portions of two jugera, allotted by the houses to their clients, to be held during pleasure, were appropriated to tillage.[18] The low prices of sheep and oxen show that cattle must have been abundant; the earliest revenue according to Pliny[g] was derived from pasture; that is, the patricians paid so much to the state for their enjoyment of the ager publicus, which was left unenclosed as pasture ground; and all accounts speak of the great quantities of cattle reared in Italy from time immemorial. Cattle then may have been a source of wealth; but commerce must have been so in a still greater degree. The early foundation of Ostia at the mouth of the Tiber, ascribed to Ancus Marcius, could have had no object, unless the Romans had been engaged in foreign trade; and the treaty with Carthage, already alluded to, proves the same thing directly and undeniably. In this treaty the Romans are allowed to trade with Sardinia, with Sicily, and with Africa westward of the Fair Headland, that is, with Carthage itself, and all the coast westward to the Pillars of Hercules; and it is much more according to the common course of things that this treaty should have been made to regulate a trade already in activity, than to call it for the first time into existence. By this commerce great fortunes were sure to be made, because there were as yet so many new markets open to the enterprising trader, and none perhaps where the demand for his goods had been so steadily and abundantly supplied as to destroy the profit of his traffic.