Identification: the river Yare
There seems little doubt as to the identification, but the name itself has puzzled scholars in the past. It may be that there was originally an s between the i and e, and that the first n was originally an r, sernus then being a river-suffix like the sarna of Maviasarna and the senna (probably originally serna) of Raxtomessasenna. Garisernus (Gariennus) would be a river-name of the kind in which a river-element is used as a suffix to a place-name (other examples are given in Chapter 19, 7.4). The place-name in this case is the old-style element gar meaning ‘steep hill’, and there are some steep slopes close to the Yare once one gets away from the extensive area of flat land between the coast and Norwich, for example at Norwich itself.
But there is a problem regarding the form of the river-element sernus, quite apart from the us ending, which can’t be original. The river-letters s and r correspond respectively to the hill-letters r and m and these hill-letters occur in the chronological order first m and then r in East Anglia, as seen in the place-names Combredovio and Camborico. One would thus expect the river-element in Gariennus to have the form resnus. The answer to this little mystery will be that Garisernus is a river-name of the kind discussed in Chapter 19, 11.3. After the changeover to inversion-type names the Iceni will have moved their river-letter s to the front of the river-suffix, the river-suffix thus becoming inversion-type.
[This page was last modified on 06 April 2021]
[NB. Detailed information as to the different river-letters and as to how they were combined to form compound river-names, together with information as to the four categories of Celtic river-names, is given in Chapter 19: the rivers of Roman Britain. Detailed information as to the different hill-letters is given in Chapter 1 and information as to how the hill-letters were combined to form compound place-names is given in Chapter 2]