Why did nationalist movements encourage the preservation of folk music in the 19th century?

In the 19th century, nationalist movements encouraged the preservation of folk music because it was viewed as the authentic, spontaneous expression of a nation’s unique identity and common experience.12

During this period, Western intellectuals began to venerate folk and peasant life, viewing folk music as a creation of the people—das Volk—that remained unencumbered by the aesthetic theories and self-consciousness of elite art music. This shift reflected a move away from a cosmopolitan, Europe-wide "polite society" toward a belief in diverse, vertical national cultures rooted in native soil.13

Nationalist movements utilized folk tunes, dances, and themes from folklore to develop distinctive national repertories in art music. By collecting and publishing these materials, scholars and composers sought to define and unify their respective nations, often using folk music as a "fructifying source" to evoke a specific ethnic group or national character. Consequently, the preservation of these traditions became a vital project for those seeking to establish a cultural identity independent of dominant, transnational artistic influences.1423