Answer
Johannes Brahms was a close collaborator of Joseph Joachim. They met in 1853 and immediately became friends. Joachim was a talented violinist and Brahms was a talented pianist. They played chamber music together and also composed together. Brahms's Violin Concerto was written for Joachim and Brahms dedicated the work to him. Joachim was a great supporter of Brahms's music and helped to promote it.