The 3.2-hectare (8-acre) fort established by the Romans near the mouth of the River Taff in AD 75, in what would become the north western boundary of the centre of Cardiff, was built over an extensive settlement that had been established by the Romans in the 50s AD.
The fort was one of a series of military outposts associated with Isca Augusta (Caerleon) that acted as border defences.
Current developments include the continuation of the redevelopment of the Cardiff Bay and city centre areas with projects such as the Cardiff International Sports Village, a BBC drama village, Sporting venues in the city include the Principality Stadium (the national stadium for the Welsh rugby union team), Sophia Gardens (the home of Glamorgan County Cricket Club), Cardiff City Stadium (the home of Cardiff City football team and the Wales football team), Cardiff International Sports Stadium (the home of Cardiff Amateur Athletic Club), Cardiff Arms Park (the home of Cardiff Blues and Cardiff RFC rugby union teams) and Ice Arena Wales (the home of Cardiff Devils ice hockey team).
) is the capital and largest city in Wales and the eleventh-largest city in the United Kingdom.
It was likely made up of traders who made a living from the fort, ex-soldiers and their families. Contemporary with the Saxon Shore Forts of the 3rd and 4th centuries, a stone fortress was established at Cardiff.
Similar to the shore forts, the fortress was built to protect Britannia from raiders.
Original Roman work can, however, still be distinguished in the wall facings.
A town grew up in the shadow of the castle, made up primarily of settlers from England.
The antiquarian William Camden (1551–1623) suggested that the name Cardiff may derive from "Caer-Didi" ("the Fort of Didius"), a name supposedly given in honour of Aulus Didius Gallus, governor of a nearby province at the time when the Roman fort was established.