The famous Hungarian Dances of Brahms were originally written for the piano solo and for four hands. The pieces got such huge popularity, until today, that many arrangements, including from the composer itself were made. Most famous are the arrangements for the orchestra and the violin with piano.
The arrangements for violin and piano were made by Joseph Joachim, Brahms his great friend. They started to arrange them during their trip through Transilvania in the fall of 1879 where they made a grand concert tour. Even though Brahms was not a concertizing pianist anymore, he did accompany Joachim with solo-pieces, sonatas and even concerto's (including his own which he started to write in 1878 and premiered on the first of January 1879.
The nineteenth century was a century in which the nationalistic idealism became very popular. Liszt, Chopin and Brahms wrote many compositions that had to do with Hungary, Poland or other countries. Though it was not typical to imitate other cultures music, like Mozart with the turkish influences or the bagpipe imitation in for example his third violin-concerto, the actual compositions of smaller sized pieces, compared to sonata's, was a new thing. This tradition of pagan-nationalistic inspirations went on in the twentieth century with for example Bela Bartok and Kodaly or the Soviet composers like Prokofiev and Shostakovich.