Llongborth, mentioned as the battle site in the Gereint Elegy, could be a placename, but it could equally well mean 'sea-port', a perfectly ordinary common noun.
   Llongborth is believed by some authorities to have been Portsmouth, and the name literally signifies the 'Haven of Ships'. But Lady Guest in her Mabinogion notes informs us that other of her contemporaries including Reverend T. Price supposed it to be Langport, in Somersetshire. This opinion was founded on the similarity of the names, and the locality; Langport being situated on the river Parret, the Peryddon of the Welsh bards, and the Pedridan of the Saxon Chronicle. This might be strengthened by the claim of nearby Sherborne Abbey which claims to have been granted land in Devon by a king Geraint.
   Longborth could also be associated with Portchester, the site of a fort of the Saxon Shore which has associated with it a number of Germanic burials closely akin to those in Sussex.
   As a common noun, it might be strengthened by the occurrence of Geraint ap Erbin in Triad 14 as one of the Three Seafarers of Britain and signify that the battle where he fought and died was a sea port.