Quintet for Piano and Strings in E flat major, Op. 44 by Robert Schumann
was on NPR this morning on my way to work.

I am not familiar with this work, but the slow or 2nd movement's opening
theme is something I have been looking for for a long time.

I remember it as being older than Schumann.  Is this perhaps a quote or
paraphrase of another work, perhaps by Schubert or even Beethoven?

Thanks in advance,

Bill