The Greek scholar and writer Dionysius of Halicarnassus (modern Bodrum on the west coast of Turkey) came to Rome around 30 BC. He wrote a history of Rome (Antiquitates romanae, Roman antiquities) from the earliest origins to the First Punic War. He also wrote letters and essays on literary criticism (Scripta rhetorica).

Antiquitates romanae 3, 44
The river [Tiber] widens considerably as it reaches the sea and forms large bays, like the best sea harbours. And, most surprising of all, it is not cut off from its mouth by a barrier of sea sand, which is the fate even of many large rivers. It does not wander into changing marshes and swamps, thereby exhausting itself before its stream reaches the sea, but it is always navigable and flows into the sea through a single natural mouth, driving back (with the force of its current) the waves of the sea, though the wind frequently blows from the west and can be dangerous. Ships with oars, however large, and merchantmen with sails of up to 3,000 [amphorae] capacity enter the mouth itself and row or are towed up to Rome; but larger ships ride at anchor outside the mouth and unload and reload with the help of river vessels.

Translation: R. Meiggs, Roman Ostia, pp. 51-52.

Antiquitates romanae 12, 1-4
(440 BC)
When he [Sp. Maelius] had made his third trip to the maritime districts of Italy and had sailed back to Ostia, the seaport of Rome, bringing many merchantmen laden with corn from Cumae and the harbours round Misenum, ...

Translation: Loeb, E. Cary.