This is indeed correct! I'm surprised to not find this indicated, since it would only serve to make listeners check out Purcell's works, too. I don't have the CD, so I'll assume that it's indicated in the liner notes somewhere.
> Track 18, "Nixon’s Walk" is actually an adaptation from the 3
> last pieces from "Dido and Aeneas" by English composer Henry
> Purcell. The pieces are called "Thy Hand, Belinda; Darkness Shades
> Me", "When I Am Laid In Earth" and "With Drooping
> Wings" and they are some of the most beautiful pieces I have ever
> heard, when performed and sang as it was actually written by Purcell.