Dvořák wrote lots of kinds of music. Although he based his style on the classical forms such as those of Beethoven, they also show the influence of Czech folksong. He lived at a time when Nationalistic feelings were felt very strongly by the Czech people. Smetana wrote music which was very Czech in character. Dvořák learned from Smetana’s music, but never imitated his style. Only five of his nine symphonies were known in his lifetime. When the other four were discovered and published in the 1960s the symphonies were all renumbered. The last three symphonies, numbers 7, 8 and 9 (which used to be called numbers 2, 4 and 5) are the most often performed. The Ninth Symphony: "From the New World" is one of the most popular symphonies ever written. The two sets of Slavonic Dances are extremely well-known. They are often played as a piano duet. He wrote concertos for the violin, cello and piano. Dvořák wrote many operas (the best known of which is "Rusalka"); chamber music (including a number of string quartets, and quintets); songs; choral music; and piano music.