Through R.G. Collingwood, his colleague at Pembroke College, Oxford between 1925 and 1936, we catch a glimpse of Tolkien pondering what the lost story of Nodens might include.
Collingwood’s Archaeology of Roman Britain contains a chapter on Inscriptions that names “Nodens the god of Lyndey” together with “Sul the goddess of Bath” two of “the very numerous non-Roman divinities whom the religious life of the Empire welcomed with its characteristic tolerance” (1930 p.166).
Rounding off long years of archaeological study, Collingwood six years later published Roman Britain. In a footnote in a chapter on Religion, he explains that Tolkien has told him that “the Celtic nominative” of the goddess of Bath “can only be Sulis” (1937, p. 264). He then offers a speculation on the meaning of the name, which he intimates is from Tolkien:
The Celtic sulis may mean ‘the eye’, and this again may mean the Sun.
Lydney Park and Bath are less than thirty miles away across the River Severn: Nodens and Sullis dwelled on opposite sides of the border made between England and Wales by the Avon valley. I think we catch a glimpse here of Tolkien wondering how their stories became entangled when Nodens the hunter caught the eye of Sullis the sun-goddess.