Place name origins only have little relation to the Roman names (e.g. Chester - 'Deva', Winchester - 'Venta Belgarum' etc.). Many English places derive part of their name from the river upon which they were built, but in the 16th century many English rivers were renamed with back-formations from towns on their banks. Cambridge, perhaps uniquely, illustrates both effects: originally "Grontabricc", a bridge on the Granta, the name became "Cantebruge" and then "Cambrugge", from which the river was renamed Cam. The vast majority of place names in Wales are Welsh by origin, containing elements such as Llan-, Aber-, Pen- etc. Along the south
Venta Silurum Roman temple, perhaps dedicated to Mars and the Celtic god Ocelus, have been identified on the site. A bowl with a chi-rho symbol shows that the worship of early Christian worship had begun in the late 3rd century. Following the withdrawal of the Roman legions from Britain, the town remained occupied until at least the mid-5th century. Early Christian worship was still established. The town might have had a bishop. A monastery was founded by Saint Tatheus in the 6th century. The site of the present church occupies part of an early Christian cemetery. The name "Venta" gave its name