According to Tacitus' biography of Agricola, the Silures usually had a dark complexion and curly hair. Tacitus hinted that they may have crossed over from Spain at an earlier date due to their appearance. Genetic studies carried out by the University College London, Oxford University and the University of California have suggested that most Welsh, and Celts people share in part (Y-chromosomes, mtDNA) with the Basque people who originated in northern Iberia during the Paleolithic. "But it is still unclear whether the link is specific to the Celts and the Basques, or whether they are both simply the closest surviving relatives of the early population of Europe"
The Iron Age hillfort at Llanmelin near Caerwent has sometimes been suggested as a pre-Roman tribal centre, but the view of most archaeologists is that the people who became known as the Silures were a loose network of groups with some shared cultural values, rather than a centralised society. Although the most obvious physical remains of the Silures are hillforts such as those at Llanmelin and Sudbrook, there is also archaeological evidence of roundhouses at Gwehelog, Thornwell (Chepstow) and elsewhere, and evidence of lowland occupation notably at Goldcliff.
The Silures made a fierce resistance to the Roman conquest about AD 48, with the assistance of Caratacus, a military leader and Prince of the Catuvellauni, who had fled from further east after his own tribe was defeated.
The first attack on the Welsh tribes was made under the legate Publius Ostorius Scapula about 48 AD. Ostorius first attacked the Deceangli in the north-east of what is now Wales, who appear to have surrendered with little resistance. He then spent several years campaigning against the Silures and the Ordovices. Their resistance was led by Caratacus, who had fled from the south-east (of what is now England) when it was conquered by the Romans. He first led the Silures, then moved to the territory of the Ordovices, where he was defeated by Ostorius in 51 AD.
The Silures were not subdued however and waged effective guerilla warfare against the Roman forces. Ostorius had publicly said that they posed such a danger that they should be either exterminated or transplanted. His threats only increased the Silures' determination to resist and a large legionary force occupied in building Roman forts in their territory was surrounded and attacked and only rescued with difficulty and considerable loss. They also took Roman prisoners as hostages and distributed them amongst their neighbouring tribes in order to bind them together and encourage resistance.
Ostorius died with the Silures still unconquered, and after his death they won a victory over the Second Legion. It remains unclear whether the Silures were actually militarily defeated or simply agreed to come to terms, but Roman sources suggest rather opaquely that they were eventually subdued by Sextus Julius Frontinus in a series of campaigns ending about 78 AD. The Roman Tacitus wrote of the Silures : 'non atrocitate, non clementia mutabatur' : changed neither by cruelty nor by clemency.
The town of Venta Silurum (Caerwent, 6 miles west of Chepstow) was established in 75 AD. It became a Romanized town, not unlike Calleva Atrebatum (Silchester), but smaller. An inscription shows that under the Roman Empire it was the capital of the Silures, whose ordo or "county council" provided for the local government of the district. Its massive Roman walls still survive, and excavations have revealed a forum, a temple, baths, amphitheatre, shops, and many comfortable houses with mosaic floors, etc. In the late 1st and early 2nd century, the Silures were given back some nominal independence and responsibility for local administration. As was standard practice inscriptions reveal the Romans matched their deities with local Silurian ones, and the local deity Ocelus was twinned with Mars, the Roman god of war.
Caerwent seems to have continued in use in the post-Roman period as a religious centre and the territory of the Silures later became the Welsh Kingdom of Gwent, Brycheiniog, Gwynllwg and Glamorgan. Some theories concerning King Arthur make him a leader in this area. There is evidence of cultural continuity throughout the Roman period, from the Silures to the kingdom of Gwent in particular, as shown by leaders of Gwent using the name "Caradoc" in remembrance of the British hero Caratacus