I once heard a lecture by the late great critic and pianist (or, as he would have said, pianist and critic) Charles Rosen on two strands of Romanticism: a backward-looking “classicizing” one (exemplified by Mendelssohn and Brahms) and a forward-looking “advanced” one (exemplified by Schumann and Chopin–and later, of course, Wagner).  In a Q & A period that followed, I asked Rosen where Schubert fit into this scheme. I was expecting Rosen to say that Schubert combined elements of both strands of Romanticism, but he surprised and intrigued me by suggesting that the case of Schubert was even more special still: that Schubert stood off to his own, inimitable side of the ‘classicizing’/’advanced’ dichotomy, though he was also the recipient of a direct, intravenous magic-drip from from Mozart.  (I’d say Schubert’s early symphonies also indicate receipt of a healthy dose of Haydn–but then what composer of the time wasn’t hugely influenced by Haydn? Beethoven actually took composition lessons from Haydn for a while, but then dropped them, grumbling that the elder master had “nothing to teach me.” Ironic, since Beethoven had already learned the better part–in a couple of senses–of what he knew about music from, if not Haydn’s lessons, Haydn’s works.)

Rosen was surely onto something when he said that Schubert was Mozart-infused, but there’s at least one case in which the influence seems to run the other way. I’m thinking of a remarkable passage in the slow movement of the Mozart’s G Minor String Quintet.

At the risk of telling you what you may well already know, the last three of Mozart’s four string quintets, in G minor, D major, and E-flat major respectively, are among his great works in any genre.  (Not that his first string quintet, an early work in B-flat major, isn’t considerable and–especially in its minuet–cherishable itself.) The slow movement of the G Minor (beginning at 16:23 in this clip) has its share of wonders, but one of them stands out, in its sheer unaccountability, not only in this quintet but in Mozart’s work as a whole. At 18:49 in the clip, a theme enters whose simple, “oom-chuck” accompaniment and surpassing lyricism make it sound like an emissary from another world.  The world in question is the future: in particular the province of it where Schubert lived. It’s as though Mozart saw what music would be forty years on, and demonstrated that he could not only envision it but produce an unbeatable example of it. (I’m not sure even Schubert could have conceived the impossibly beautiful echo with which Mozart dance-partners his theme at 19:03.) Having brought off this unparalleled bit of time-travel, Mozart returns his movement from the nineteenth century to the eighteenth as though nothing out of the ordinary had happened. (He may have visited the future, but apparently had no inclination to move there.)

The late great critic Donald Tovey once accused Haydn, in an immortal phrase, of “impudent prophetic plagiarism.” (The bit Haydn had pilfered was a spot in Brahms.) If this charge applies anywhere else in music, it would be to Mozart’s shameless appropriation of Schubert.