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
New England town were not part of this process in southeastern New Hampshire, such as Exeter. Once there were enough residents in a town to formally organize a town government, no further action was necessary to incorporate. This practice can lead to inconsistencies in the dates of incorporation for towns in this region. Dates given in reference sources sometimes reflect the date when the town was chartered, which may have been long before it was settled, and not the date when its town government became active. In other parts of New England, some "future towns" were laid out along these lines, but such