I've noticed some pieces by Brahms, such as cadenzas for various Beethoven piano concertos, bearing notices like "Incorporating material composed by Clara Schumann."
I'm sure that many of his works would have been influenced by her - many of them were written for her, and she would have been the first to hear them performed and suggest changes or improvements.
Virtually all of the biographical sources I have read are unanimous on the fact that the Brahms-Clara Schumann relationship was completely platonic and never became physical. As Brahms (being a perfect gentleman, unlike today's "kiss-and-tell" celebrities) always insisted that nothing happened between them, I am inclined to take his word for it and leave it at that. But even in their day, their friendship was the subject of raised eyebrows and sometimes vicious rumours.
Felix Schumann (1854-1879), youngest of the eight children of Robert and Clara Schumann, born a few months after Robert was committed to a mental institution.
A picture of the young Johannes Brahms.
(but then, I'm no expert in genetics, or photography.) Just saying.
aldona
“all great composers wrote music that could be described as ‘heavenly’; but others have to take you there. In Schubert’s music you hear the very first notes, and you know that you’re there already.” - Steven Isserlis