Fairies in Britain, how they were affected by Greek and Roman stuff during the Renaissance, etc.

 This deserves a ton of study... this website has some great research. 

https://britishfairies.wordpress.com/2019/01/20/anti-paracelsus-the-man-who-messed-up-faery/

Katharine Mary Briggs

That whole thing on Paracelsus is interesting and funny.

Note that the website author loves
Katharine Mary Briggs
so keep her in mind. She compiled all sorts of fairy info.

And check: 

Paracelsus and folk tradition

Now, we already know that classical mythology had started to taint native beliefs as a result of the renaissance rediscovery of Greek and Roman legends.  British fairies were regularly made synonymous with Mediterranean fauns and such like:

some are of fyre, and some of the ayre,/ Some watrye and some earthly, and some golden and fayre/ Some lyke unto sylver…” (The Buggbears, George Gascoigne, 1565) 

Funky -YRE spellings. Well doesn't the fyre, ayre, watrye just tie right into my post a couple back on weird old word pronunciations and WATER and FIRE being special. 

Does duergar come from .. The Anglo-Saxon word for dwarf, dweorg, ??