Conquerors: A computer animation showing how the fortress, garrison (centre) and port may have looked like in AD74. The river Usk is to the right.

The remains of a 2,000-year-old Roman port - only the second to be found in Britain - have been unearthed by archaeologists in South Wales.

The well-preserved remains were found outside the Roman fortress in Caerleon, which was constructed in AD74 during the final conquest of the fierce Celtic tribes.

Known as Isca, it was the headquarters of the Second Augustan Legion - one of four legions who invaded Britain during the reign of Emperor Claudius. It was constructed under the governorship of Julius Frontinus.

Nine trenches were opened up by the team from Cardiff University for the four-week dig

The ancient port is located on the banks of the River Usk just north of the city of Newport and include the main quay wall, as well as the landing stages and wharves where ships would have docked and unloaded their cargoes. It is only the second known Roman port after London.

A team from Cardiff University made the find during excavations of the ‘Lost City of the Legion’, a suburb of public-style buildings discovered in August last year.

The trenches have also revealed remains from buildings that could include marketplaces, administrative buildings, bath-houses and temples, hidden under the soil for two millennia.

Dr Peter Guest, who is leading the excavation team said: 'What we have found exceeds all expectations. We are excavating the remains of a previously unknown complex of important Roman buildings that survive remarkably well considering how long they have lain underground.

'The port or harbour is a major addition to the archaeology of Roman Britain and adds a new dimension to our understanding of Caerleon as we can start to think about how the river connected the fortress and Wales to the rest of the Roman Empire. 

WHO WAS GOVERNOR JULIUS FRONTINUS?

Sextus Julius Frontinus was a Roman soldier and governor of Britain from AD 73-78.

During his time he subdued the powerful and warlike Silures tribe in Wales and oversaw the building of seven forts - including the legionary fortress Isca Silurum.

He was interested in public improvements and saw the construction of via Julia - a road running through Somerset, Gloucester, Monmouth, and South Wales.

Before his governorship his was a high-ranking magistrate in Rome.

He returned to the city after his governorship ended. He was put in charge of the aqueducts of Rome in AD 97 and wrote a history and description of the water supply.

He died in AD104 at the age of 69.

(Below) A bronze ox-head bucket mount

'We believe that the port dates to period when the Legions were fighting and subduing the native tribes in western Britain and it’s incredible to think that this is the place where the men who took part in the conquest would have arrived.

'Our trenches are also looking at several buildings adjacent to the port and we have also found rooms with under-floor heating systems, collapsed walls and roofs, as well as many thousands of objects made, used and lost during the Roman period.'

The extensive excavation site provides the only opportunity to study the Roman legions in Britain. There were three permanent legionary bases in Roman Britain - Caerleon, Chester and York, but the last two are much more difficult to excavate because their remains are mostly buried under cities.

The second legion was based in Isca fortress (imagined in this computer graphic) under Governor Julius Frontinus

Finds: Hundreds of shards of pottery was found on the South Wales site as well as coins from the first and second centuries

Nine trenches were opened up by a team of 35 staff and students from Cardiff University for the four-week dig.They were joined by field archaeologists from around the UK and volunteers and expect a visit from Channel 4's Time Team.

In one trench they found 'beautifully rendered walls, and finding large quantities of oyster shells and pottery'.

Another revealed painted plaster from a hypocaust floor. This was where the floor was raised on pillars to allow heated water to pass underneath. They have also found numerous coins from the first and second centuries.

Another imagined view of the settlement, that would have housed Roman soldiers battling fierce tribes of Celts