Many of the groups listed are highly obscure: some can only be identified and localised with the aid of place-names, and a few cannot be confidently localised at all.
Many of the territorial groups listed are highly obscure, however: some can only be identified and localised with the aid of their fossilized survival in place-names, like the "Hicce" in Hitchen, Hertfordshire. A few cannot be confidently localised at all.