Planktus David by Peter Abaelard

I found the story of Abaelard and Heloise to be very interesting (from class on 9/28/11).  I decided to see what music I could find of his, and the first thing I came across on Naxos was this piece called Planktus David.  I believe that in class we only discussed number VI, but what I found on Naxos was the entire work.  It is monophonic, completely a capella, with no instrumental accompaniment.  Even if I didn't know what the work was about I would still say that it has a melancholy sound to it.  It "feels" sad to me, as I attempt to listen not to the tangibles, but the undefinable qualities.  The music is set to a poem by Abaelard taken from the story in second Samuel (from the Old Testament) in which David laments the deaths of Saul and Jonathan.  The entire recording is over 15 minutes long, so the piece is actually quite long if one does all six parts.  The music itself doesn't seem to change mode/key nor deviate much in it's melodic content.  Is the inspiration behind this piece Abaelard's own tragic life story?  I am of course, speaking of the love story of Abaelard and Heloise.  I hope to have more time someday to dig deeper into that story.