Moreover, the Tiber formed, from the earliest times, the frontier defence of the Latin stock against their northern neighbours. No place is better qualified than Rome to be both the _entrepôt_ of the Latin river and sea commerce and the frontier fortress of Latium. She combined the advantages of a strong position and the immediate neighbourhood of the river; she commanded both banks of the stream down to its mouth; she was equally convenient for the river-ships descending the Tiber or the Anio or, in those days of moderate-sized vessels, for those designed for the sea; and she afforded better protection against pirates than the towns lying immediately on the coast. That it was to these commercial and strategical advantages that Rome owed, if not her origin, at least her importance, numerous proofs are forthcoming, which are of far greater importance than the data furnished by historical romances. With these are connected her early relations with Cære, which was to Etruria what Rome was to Latium, and consequently became the city’s closest neighbour and commercial ally; thence came the extraordinary importance of the bridges over the Tiber, and of bridge building generally in the Roman commonwealth, and hence the galley in the city arms. This was also the origin of the ancient Roman harbour dues, which were originally imposed only on goods for sale (_promercale_), and not on those which passed to and from Ostia for the shipper’s own use, and thus were really a tax on trade. And hence, to anticipate, arose the relatively early appearance of coined money in Rome and the commercial treaties with states over-sea. Thus, from this point of view at any rate, Rome may be regarded as the legend implies, rather as a created than a gradually developed town and rather as the youngest than the oldest of the Latin towns. Doubtless the land had been already to some extent brought under cultivation and towns planted on the Alban hills as well as many other heights of the surrounding country when the Latin frontier emporium rose on the Tiber.