I was recently listening to the composition John Williams - Indiana Jones and the Last Crusade: The Penitent Man Will Pass and was wondering if the first few notes of the theme of that composition are a reference/citation/parody of the third movement of the Trio Sonata No. 2 In C Minor BWV 526 by Bach. I could not find a score of the Williams piece though to compare. Does anyone know if this is the case here?
As noted in comments, it's impossible to know this without hearing John Williams's thoughts on the matter.
My sense, based on just the evidence of the music, is no. First off, note that the "citation" is actually not just from The Penitent Man Will Pass, but is actually the "Grail theme" of the entire movie which occurs numerous times at references to the Holy Grail.
But is there really enough here to claim this is an allusion or reference? The melody of the fugue begins with a 5-1 (sol-do) leap, as do numerous fugues. The only distinctive quality of the subject is the move to flat 7 in the melody, harmonizing a minor v chord. That is unusual as an opening gambit for a fugue, and I can't draw any other fugue subjects to mind right away that do that in Bach, but I'm not sure. I can think of a few 17th-century fugues/ricercars that begin like this. But it gives the fugue a distinctive "modal" quality, which sometimes appears in Bach. (Tonal answers in fugues frequently move to the minor v too, just not generally so early.) After that, there's a little set of three notes that go faster: 1-2-3 in the scale. Beyond that, the fugue bears no resemblance to the movie theme.
We're talking about six notes here, and if the B-flat were a B-natural, this would be about the most common melody one could imagine for a fugue subject.
Meanwhile, what doesn't the Bach have? It has a faster speed-up for the 1-2-3 gesture. It doesn't have the distinctive heavy VI-V-i cadence that the Grail theme has. And the Bach theme launches into completely different stuff after six notes.
Basically, the only distinctive feature both melodies share is the emphasized lowered scale degree 7. One note. But that's a common feature of melodies evoking a "modal" character, as Williams undoubtedly was trying to do to give the music a more "ancient" or "medieval" kind of sound. (It's not an actual medieval sound, but it's one movie music trope to represent "olden times," which comes out of 19th century opera, e.g., Wagner.)
Anyhow, could Williams have been thinking of this Bach piece when he wrote the music? Sure, I suppose. But why? Why reference this Bach piece? It's not like it has any sort of symbolic link with the movie's themes or the Holy Grail. And if it was inspired by Bach, it's certainly not enough to really be a recognizable reference to this specific piece.
In sum, I don't think we can rule out inspiration for Williams. But an intentional reference/citation? I don't think there's enough. As with most musical connections of a few notes that people hear, they're often coincidences.