A few days back, I went live with my page on Germania Inferior—which is to say, Lower Germany (not ‘inferior’ in the usual English sense). This is worth mentioning on several scores: (1) it’s the first ‘geographical’ page on http://www.deomercurio.be that concerns a non-Celtic region; (2) for a different reason,* I didn’t go through and enumerate the attestations of deities on inscriptions; (3) it rounds out the provinces that I have pages for very nicely—I now only need to do provinces along Gaul’s southern extremities; (4) it’s quite nearby my Treveran home base in Gaul, and in fact there were Treveri among those who left religious inscriptions in neighbouring Germania Inferior.
What I’ve done in the geographical pages of http://www.deomercurio.be in general is to list, sort, and enumerate inscriptions of religious interest in each of the (late Roman) provinces of Gaul. I do think this is worth doing, but obviously there’s a limit to what it can tell you. Learning that god X was worshipped under the name Y in such-and-such a region is great and good, but it can never exclude the possibility that name Z was also used, that name Y was used elsewhere (but never written down), that god X was not worshipped elsewhere, or least of all that god Q was not worshipped in the same place but never mentioned on an inscription. Also, all inscriptions are not created equal. The cursive scrawl on the base of a statuette should probably not be counted in the same way as the dedicatory inscription of a temple or even an altar. Finally, non-inscribed monuments need to be taken into account as well. (I probably didn’t make those caveats sufficiently clear on the website, so I should take another look at that.)
In any case, I think the format of the Germania Inferior page will do: it’s more qualitatively and less quantitatively driven, although it also highlights the deities who seem to dominate the religious scene in that area (consisting of today’s southern Netherlands, much of Belgium, and a slice of western Germany). These deities include the great and charming Nehalennia, who watches over sea voyages and provides the blessings of material prosperity (and no doubt other kinds of prosperity as well); Hercules Magusanus, whom the excellent band Heidevolk have a song in honour of,** and who would become the patron of the divine Postumus; Jupiter and Juno, the great protectors of the eternal city; Mercury, worshipped as Cissonius (a Celtic epithet, we think), Arvernus (attention: Puy de Dôme!) and Gebrinius (at Bonn); and above all the Matronæ, who are attested in an incredible profusion of monuments, often inscribed and often beautifully carved.
* Namely that there are just so many inscriptions from Cologne that every time I try to start going through them, I despair of ever finishing!
** The context is ironic (the Batavians are pledging their dedication to the Roman Empire, and calling on Hercules Magusanus to witness the deed, just before rebelling against Rome). However, the song seems to work in its own right as well.