Ostia (or Ostia Antica) lies 15 km from the city of Rome for which it served as the city's principal port and harbour throughout antiquity. The name derives from 'os' or 'ostium' which means 'mouth' and refers to the city's location at the mouth of the river Tiber. Although originally situated at the mouth of the river, because of silting, it is now some 3 km east of the present river mouth although still located on the south bank of the Tiber.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Ostia/.