I love that quote!
It's the golden bit that makes me think its connected to the Sun. More specifically, the golden horse - many of Europe's solar deities are horse riders. And then there's the name "Zil". This has to be taken in the context of the enormous weight of "circumstantial" evidence connecting this (approximate) sound to solar ideas across Europe. These three factors together are what is suggestive to me. If it was a folk-memory of golden grave goods then why the horse? Is there an historical King Zil?
You should know that I never write these things as though they are certain facts. I present them merely as suggestive possibilities.