Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
Nullity of the Roman Marine Police
This state of matters clearly shows, as we have partly indicated already,(5) how the Romans kept--or rather did not keep--order on "their sea."
5. Cf. IV. I. Piracy
The protectorate of Rome over the provinces consisted essentially in military guardianship; the provincials paid tax or tribute to the Romans for their defence by sea and land, which was concentrated in Roman hands. But never, perhaps, did a guardian more shamelessly defraud his ward than the Roman oligarchy defrauded the subject communities. Instead of Rome equipping a general fleet for the empire and centralizing her marine police, the senate permitted the unity of her maritime superintendence-- without which in this matter nothing could at all be done--to fall into abeyance, and left it to each governor and each client state to defend themselves against the pirates as each chose and was able.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-02-rule-sullan-restoration.asp?pg=11