At the end of 19, the Bulgarian workers' movement gradually developed. The establishment of Social Democratic Party (189 1) and the spread of Marxism promoted the emergence and development of proletarian literature. Di Polyanov (1876- 1953) was the first proletarian poet, and his poems such as The Tree of Death (1905) called on the proletariat to fight for crushing the old world. The prose of writer Ge Kirkov (1867- 19 19) attacked the bourgeois government. Di Blagoev (1856- 1924) is the founder of Bulgarian Marxist literary theory. Bakaloff's (1873- 1939) and Pavlov's (1890- 1977) activities in literary theory had a great influence on the development of literature.
During and after World War I, a number of revolutionary poets emerged in Bulgaria, such as Yasinov, Smir Nenski and Vapp Sarow.