I played over the music of that scoundrel Brahms. What a giftless bastard! It annoys me that this self-inflated mediocrity is hailed as a genius. Why, in comparison with him, Raff is a giant, not to speak of Rubinstein, who is after all a live and important human being, while Brahms is chaotic and absolutely empty dried-up stuff.Pyotr Ilyich Tchaikovsky, diary entry, 9 October 1886.
Tschaikovsky sat down and listened till the Trio [Brahms's C- trio, op. 101] was finished. The personality of Brahms seemed to please him, but the music left him quite cold, and he was too conscientious a man to say anything pleasant to Brahms which he really did not feel about the Trio. A certain unpleasantness, or at least a want of harmony, might have been caused by this circumstance, but at that moment the door opened and Grieg and his wife entered! These two had the art of always spreading around them a pleasant and sunny atmosphere, and this was the case now. Tschaikovsky had never seen them before, but he loved Grieg's music, and he was immediately attracted to him. In most cheerful mood we all sat down to dinner, Madame Grieg being placed between Brahms and Tschaikovsky. It was not long, however, before she rose and said that it made her much too nervous to sit between them. Grieg sprang to his feet and changed places with his wife, and said: "But I have the courage." So the three composers sat together and there was a great deal of fun. I seem to see Brahms now as he drew towards him the dish of strawberry jam and said that no-one else should have any, and how Tschaikovsky laughed. It was more like a children's party than a group of great musicians.The first meeting of Brahms and Tchaikovsky, as recounted by violinist Adolph Brodsky (Musical Times, April 1903).
Johannes Brahms: born May 7, 1833
Pyotr Ilyich Tchaikovsky: born May 7, 1840
I wonder if they ever realized? It seems unlikely.