Just for fun, I was looking through my mother's 1938 college textbook,
entitled Symphony Themes -- simply a compendium of symphony themes.  The
usual suspects are there (Beethoven, Mozart, Haydn, Schumann, Brahms),
but also quite a few odd ducks.  Since such a book reflects, consciously
or unconsciously, a judgment of importance -- or why else would you go
to the trouble of compiling themes from a work? -- I thought it interesting
to list those works at one time regarded as canonical and now practically
invisible:

Bax: Symphony No. 3 in C
Bennett, Robert Russell: Abraham Lincoln Symphony
Bloch: Symphony "America"
Chausson: Symphony in Bb
Copland: Dance Symphony
Glazunov: Symphony No. 5 in Bb
Goldmark: Symphony in Eb "Rustic Wedding"
Hadley, Henry: Symphony No. 4 "North, East, South, West"
Hanson: Symphonies 1-3
Harris: Symphonies 2-3
Hill, Edward Burlingame: Symphonies 2-3
Honegger: Symphony No. 1
d' Indy: Symphony No. 2 in Bb
Mason, Daniel Gregory: Symphony No. 3 in Bb "Lincoln"
Mendelssohn: Symphony No. 5 "Reformation"
Sowerby: Symphony No. 2
Strauss: Alpensinfonie; Aus Italien
Stringham: Symphony No. 1 in bb

Things that the editors seem to have gotten right: Sibelius (all 7
symphonies) and Elgar.  All of Vaughan Williams's instrumental symphonies
to that point (2-4).

Not quite so right: Tchaikovsky's last three symphonies, but not the
first three.  Mahler 2-4 only.  Nothing by Stravinsky or by Hindemith.
Bruckner 4, 7, and 9 only.  Dvorak 8 and 9 only.  Prokofiev Classical
Symphony only.  Shostakovich No. 1 only.

Just another example of the fluidity of judgments on lasting worth.

Steve Schwartz