Portus Iulius

Portus Julius was the first harbour specifically constructed to be a base for the Roman western naval fleet, the classis Misenensis. The port was located near Baiae and protected by the Misenum peninsula at the north-western end of the Gulf of Naples. Portus Julius was named in honour of Octavian's great-uncle and adoptive father, Julius Caesar and the Julian clan.

Description via Wikipedia. Coordinates and heritage data from the Atika atlas.