Mark Ehlert writes:

>Neal Zaslaw suggests that this four-note motto is based on or an actual
>transcription of the beginning of a Gregorian chant, but I've never seen
>it indicated exactly which chant is being referred to.

I believe the chant is "Lamentationes Jeremiae" (did I get that right?).
Mozart uses the same chant in his "Mauererische Trauermusik" played by the
oboes.  I don't know if there is any significance to Mozart's use of a
funeral chant in his last symphony.

Eric James