The Greek historian Cassius Dio Cocceianus lived c. 155-235 AD. He came to Rome in about the year 180 and entered the Senate under Commodus. He was consul twice. His main work was the Roman History, covering the period from the arrival of Aeneas to his own second consulship. Some books have survived intact, from other books only fragments are known, and of some we only have excerpts (by Zonaras and Xiphilinus).

Roman History 36, 22
(c. 68 BC)
As these operations of theirs [the pirates] met with success it became customary for them to go into the interior, and they inflicted many injuries on those even who had nothing to do with the sea. This is the way they treated not only the distant allies of Rome, but even Italy itself. For, believing that they would obtain greater gains in that quarter and also that they would terrify all the others still more if they did not keep their hands off that country, they sailed into the very harbour of Ostia as well as other cities in Italy, burning the ships and pillaging everything. Finally, as no attention was paid to them, they took up their abode on the land, disposing fearlessly of whatever men they did not kill, and of whatever spoils they took, just as if they were in their own land.

Roman History 48, 43, 5
(38 BC)
... certain persons, becoming inspired by the Mother of the Gods, declared that the goddess was angry with them. For this reason the Sibylline books were consulted, and they made the same declarations and prescribed that the statue should be taken down to the sea and purified in its waters. Now when the goddess was taken out a long distance from the land into the deep water and remained there a good while, being brought back only after a long time, this circumstance also caused the Romans no little fear, and they did not recover their spirits until palm trees, four in number, sprang up round about her temple and in the Forum.

Roman History 60, 11
On the occasion of a severe famine he considered the problem of providing an abundant food-supply, not only for that particular crisis but for all future time. For practically all the grain used by the Romans was imported, and yet the region near the month of the Tiber had no safe landing-places or suitable harbours, so that their mastery of the sea was rendered useless to them. Except for the cargoes brought in during the summer season and stored in warehouses, they had no supplies for the winter; for if any one ever risked a voyage at that season, he was sure to meet with disaster. In view of this situation, Claudius undertook to construct a harbour, and would not be deterred even when the architects, upon his enquiring how great the cost would be, answered, "You don't want to do it!" so confident were they that the huge expenditures necessary would shake him from his purpose, if he should learn the cost beforehand. He, however, conceived an undertaking worthy of the dignity and greatness of Rome, and he brought it to accomplishment. In the first place, he excavated a very considerable tract of land, built retaining walls on every side of the excavation, and then let the sea into it; secondly, in the sea itself he constructed huge moles on both sides of the entrance and thus enclosed a large body of water, in the midst of which he reared an island and placed on it a tower with a beacon light. This harbour, then, as it is still called in local parlance, was created by him at this time. He furthermore desired to make an outlet into the Liris for the Fucine Lake in the Marsian country, in order not only that the land around it might be tilled but also that the river might be made more navigable. But the money was expended in vain.

Roman History 60, 21, 2
When the message reached him, Claudius entrusted affairs at home, including the command of the troops, to his colleague Lucius Vitellius, whom he had caused to remain in office like himself for a whole half-year; and he himself then set out for the front. He sailed down the river to Ostia, and from there followed the coast to Massilia; thence, advancing partly by land and partly along the rivers, he came to the ocean and crossed over to Britain, where he joined the legions that were waiting for him near the Thames.

Roman History 61, 31, 4
Now all these doings, though for some time they had been either heard about or witnessed by everybody else, continued to escape the notice of Claudius. But finally, when he went down to Ostia to inspect the grain supply and she [Messalina] was left behind in Rome on the pretext of being ill, she got up a banquet of no little renown and carried on a most licentious revel.

Roman History 76, 8, 2
(A.D. 197, Septimius Severus addressing the Senate in Rome)
"For if it was disgraceful," he said, "for him [Commodus] with his own hands to slay wild beasts, yet at Ostia only the other day one of your number, an old man who had been consul, was publicly sporting with a prostitute who imitated a leopard".

Translation: Loeb, E. Cary.