Strabo Geography 3.3.1

[1] STARTING again from the Sacred Promontory, ¹ and continuing along the other side of the coast, we come to the gulf near the Tagus, afterwards Cape Barbarium, ² and near to this the outlets of the Tagus, which may be reached by sailing in a straight course for a distance of 10 stadia. ³ Here are estuaries, one of them more than 400 stadia from the said tower, on a part of which Laccaea is situated. ⁴ The breadth of the mouth of the Tagus is about 20 stadia, its depth is so great as to be capable of navigation by vessels of the greatest burden. At the flood-tide the Tagus forms two estuaries in the plains which lie above it, so that the plain is inundated and rendered navigable for a distance of 150 stadia. In the upper estuary an island is formed about 30 stadia in length, and nearly equal in breadth, which is fertile, and has excellent vines. The island lies near to Moro, ⁵ a city happily situated on a mountain close to the river, and about 500 stadia from the sea. The country surrounding it is very fine, and the ascent [of the Tagus] for a considerable way practicable for vessels of a large size, the remainder is performed in riverboats. Above Moro it is navigable for a yet longer distance. Brutus, surnamed the Gallician, made use of this city as a military station, when fighting against the Lusitanians, whom he subdued. On the sides of the river he fortified Olysipo, in order that the passage up the river and the carriage of necessaries might be preserved unimpeded. These therefore are the finest cities near the Tagus. The river contains much fish, and is full of oysters. It takes its rise amongst the Keltiberians, and flows through the [country of the] Vettones, Carpetani, and Lusitani, towards the west; ⁶ to a certain distance it runs parallel with the Guadiana ⁷ and Guadalquiver, ⁸ but parts from them as they decline towards the southern coast.