Romantic music
The Romantic period was also the period of Nationalism.  "Nationalism" means being proud of one's country.  In the 19th century  a lot of European countries as we know them were being formed.  In music a lot of composers were writing music which was typical of their country.  They often did this by using folk music.  Antonín Dvořák (1841-1904) and Bedřich Smetana (1824-1884) wrote music which sounds very Czech. Pyotr Tchaikovsky (1840-1893)  wrote music with Russian folk songs in them. Gustav Mahler (1860-1911) used German folk songs in his symphonies, and Ralph Vaughan Williams (1872-1958) collected English folk songs and put them in his music.  One of those pieces was a Fantasy on the famous tune Greensleeves.