Traditionally the city is regarded as having been founded in 633 BC by the fourth King of Rome, Anco Marzio. In truth, more in-depth archaeological research indicates the 4th century BC as its foundation date. This hypothesis is backed up by the discovery of the Castrum, a small fortified city dating back to 330 BC.
The strategic position of the city leads you to think that in the beginning Roman Emperors provided Ostia with all the necessary services to make of it a fundamental centre for trade and military operations.
For this purpose Emperor Claudius in 42 AD had a port built about 3 Km north of Ostia. The was work completed in 64-66 AD by Nero, whilst between 100 and 112 AD Emperor Trajan had a new one built - The Port of Trajan. This was better protected than the previous one, which too susceptible to harsh weather conditions.
During the Imperial Age Ostia became a true and proper cosmopolitan city reaching about 100,000 inhabitants between the 2nd and 3rd centuries AD with different ethnicities, cultures and religions living together. Their liveliness and prosperity is reflected in the structures created to host the social and political life of the time - just contemplate the shops, temples, houses, mosaics, statues, port, theatre, warehouses and spas.
The Ostia Antica Theatre is very well preserved and perhaps the most representative emblem of the whole archaeological area. It was built in 180 AD by Emperor Commodus and can hold 4000 people. It is still used for concerts and shows.
As of the 4th century, with the trade crisis and barbaric invasions, the city of Ostia began to decline and be neglected by the government until its total abandonment from the 9th century AD.
The ruins of Ostia Antica, which were largely intact, were brought to light starting from the 19th century and today represent a splendid and rare example of what a city was like in Roman times.
