I'll just drop some sources in here for now!
Sources on Belenos are unfortunately far more difficult to find than those on, say, Cernunnos.
Camulos and Belenos is an interesting read. If you read French, also check out
Le Dieu Gaulois Belenus, La Deesse Gauloise Belisama. Unfortunately, those are the only articles I have on hand, and they're both JSTOR. Also
Celtnet.
(Belenos is repeatedly identified [with varying levels of substantiation] with Apollo, Mercury, and even
Antinous, as well as Bel, Belen (Brythonic, British) and Bilé (Irish) of Celtic origin, and even Lugos, another Gaulish god. He is frequently labeled a sun/fire god, though I'd like to see some evidence on that because the assumption seems to stem from comparative mythology--I personally don't think this is a founded conclusion (
x). Another side note: though some might identify him with Apollo,
there is no evidence for integration of Belenos/Gallo-Celtic and Greco-Roman cultus.)
All this said, does anyone have any sources regarding Belenos, or UPGs/experiences?
Edit: I've also got
this map which might be useful in further research, as it documents various Belenos attestations (and two Belesama attestations). Oh, and here's
a lovely prayer!