Imperia takes its name from the Impero River, which divides the city into two parts. For centuries long, it served not only as a natural border between the two rivals, but also an administrative one. Oneglia and Porto Maurizio; the first city was under the rule of the Kingdom of Sardinia and the other belonged to the Republic of Genoa. In 1923, the two cities were joined together, but each part has retained its own particularity. Oneglia, which stretches out towards the sea, has an economy based on oil production and its port. Porto Maurizio, however, (which boasts an excellent view of the sea from its small alleys) is a medieval market town located on the Parasio promontory.