The Roman army reached Exeter around AD 50-55 during the conquest of south western Britain.
On a spur overlooking the River Exe a 42 acre legionary fortress was built. This was the base for the 5000 strong Second Augustan Legion.
The fortress occupied a commanding position overlooking the River Exe, defended on two sides by steep valleys. The defences and buildings of the fortress were constructed almost entirely from timber and clay. The one exception was the bath house which had walls of volcanic stone quarried from Rougemont Hill. It was an impressive building and was the equivalent to the modern sports hall. Nothing was known of the bath-house until it was excavated by the Exeter Museums Archaeological Field Unit between 1971-76. It lay at a depth of up to 3m below the present surface of the Cathedral Close and was covered by Saxon and medieval cemeteries. Following excavation the bath-house was covered with sand so that it will be possible to re-open the site at some future date and place it on permanent display. The remains are amongst the most impressive of any Roman bath-house in Britain.
In about 75 the legion was transferred to Caerleon in South Wales and the fortress was abandoned. A few years later work began to convert the site into a civilian town, known as Isca Dumnoniorum. Its public buildings included a forum and basilica (town hall), a market place and public baths.
In about 180-200 the City Wall was built, enclosing 93 acres, a much larger area than that of the fortress and early town. About two thirds of the City Wall remains; it has been patched and repaired over the centuries but some original Roman masonry can still be seen. The sites of the gates were retained in the following centuries but little remains of the Roman grid street pattern. Only the northern part of the High Street follows the Roman lines.
Displays of Roman finds from the city can be found in the Royal Albert Memorial Museum on Queen Street.