After the founding of Yugoslavia in the early 20th century, Njegoš was twice declared Yugoslavia's national poet, by the royal government in the 1920s and by the communist authorities following the Second World War. In 1947, the 100th anniversary of the publication of "Gorski vijenac", the government promoted Njegoš as a Montenegrin poet rather than a Serb. The change in Njegoš's ethnicity may have been related to the communist policy of Brotherhood and Unity and its promotion of a Montenegrin ethnic identity (which the communists had proclaimed distinct from that of Serbs in 1943). Njegoš' works, particularly "Gorski vijenac", have been sources of collective identity for Serbs, Montenegrins and Yugoslavs. Njegoš's works have been removed from school curricula in Bosnia and Herzegovina so as not to incite ethnic tensions, given the divisive nature of some of his works.