This Autumn Richard, Raine and I went (briefly) to Crickhowell Literary Festival. I had no idea we were in such a rich area for Welsh mythology, which has become part of our consciousness and literature. It's random finds like this that keep my imagination lively: I recommend spontaneous visits, whether or not you're an author. It loosens you up. I even recommend it where you live: act like a tourist and new pathways open (often literally).
Anyway, Wales. About ten minutes from our hotel I found a crannog, which is a setting in book 3, and the lake at Llangorse, where it’s likely Arthur found Excalibur, also holds a legendary monster, the Afanc. I’m betting Tolkien based his monster that rises from the Black Pool to guard the Doors of Durin is based on this.
The earliest known surviving literary reference to the afanc or lake monster of Llangorse is in a poem by the 15th century Welshpoet or bard, Lewys Glyn Cothi (English translation by John Rhys):
Yr avanc er ei ovyn
Wyv yn llech ar vin y llyn ...
The afanc am I, who, sought for, bides
In hiding on the edge of the lake ...
I'm on the last leg of the Book of Bera trilogy and have as yet no idea what my next book or series will be. Who knows? Perhaps a version of the Afanc will feature.