In brief: It is believed that the originality of art created by Mikalojus Konstantinas Čiurlionis (1875-1911) is determined by the intertwined features of Symbolism and Avant-gardism. As scientists analyse the “transitional" status of Čiurlionis’ works (between Symbolism and Modernism), less attention is allocated to features determined by art of his epoch, i.e., manifestations of epoch of year 1900 and Art Nouveau.