Ostia, the harbour of Rome at the mouth of the Tiber River, lies some 24 km south-west of Rome. According to legend, Ostia was founded by the fourth legendary king of Rome, Ancus Marcius (from 640 to 616 BC). The archaeological remains date back to the 4th century BC. The original urban core was a small fortified village whose inhabitants primarily lived by the extraction of salt from the marsh regions at the mouth of Tiber. Concurrent with the growing population of Rome, the need for a commercial harbour arose to handle the increased supply requirements of the big city. The city developed rapidly to become the commercial harbour of Rome but it also served as the naval base during the Punic wars. The second century AD was the period of greatness for Ostia. The city kept a lively trade and people of many different nationalities lived here. There was a large immigration from the Roman provinces and it is documented that government officers, tradesmen, and craftsmen from Northern Africa, Egypt, Turkey and Greece were present. The city consisted primarily of store buildings, granaries, market squares, a forum, a theatre, temples, baths, villas and big block of flats. Furthermore, Ostia is known for its many Mithras, underground sanctuaries and worship sites of the Persian God of light. In late antiquity, the Tiber changed its course, Ostia harbour silted up with the result that the city suffered a decline and was left over time. The city is a fantastic supplement to Pompeii as Ostia’s time of glory lies in immediate continuation of the time when Pompeii was destructed.