Дамы, тут интересный материал из Твиттера. Даг Адамс кое-что разъясняет о музыкальных темах.
Oh dear, I guess I hadn't realized that the #LOTR / #DiesIrae thing was still the subject of ongoing debates. Here it is in a nutshell:
Here's the #DiesIrae (pitch names added for non-readers):
And here's #HowardShore's Descending Third motif from #LOTR:

I've centered both on a D-minor tonality to give them a fighting chance, but as you can see, pitch and rhythmic content are different.
A musical *quote* is a definitive thing. It's (essentially) exact and it's purposeful. A musical *reference* is more objective, of course.
In this case, #HowardShore has said that the Descending Third motif is *not* a quote of the #DiesIrae, which pretty much puts it to bed.
However, if people want to call it "#DiesIrae-flavored," that's more a matter of subjective interpretation.
Personally, I think even the case for an accidental *reference* is stretching things.
After all, Sousa's "Stars and Stripes" has more in common with the #DiesIrae than #LOTR does!