Winchester more urban settlement type developed, known as an oppidum, although the archaeology of this phase remains obscure. It was overrun by the confederation of Gaulish tribes known as the Belgae sometime during the first century BCE. It seems to have been known as Wentā or Venta, derived from the Brittonic for "town" or "meeting place", or the word for "white" (Welsh "gwyn"), due to Winchester's situation upon chalk. After the Roman conquest of Britain, the settlement served as the capital () of the Belgae and was distinguished as Venta Belgarum, "Venta of the Belgae". Although in the early years of
Venta Silurum to the emerging Kingdom of Gwent (called initially "Kingdom of Guenta"), and the town itself became known as "Caer-went" or "the castra/fort of Venta/Gwent". Tradition holds that Caradog Freichfras of Gwent moved his court from Caerwent to Portskewett around the 6th century. The town lacked substantial defences until the mid 4th century when stone town walls were built. A small garrison may have been based in the town during this period. Large sections of the defensive walls are still in place, rising up to 5 metres in height in places. The walls have been described as "easily the most impressive