In addition, Cui wrote many works for piano and for chamber groups (including three string quartets), numerous choruses, and several orchestral works, but his most significant efforts are reflected in the operas, of which he composed fifteen of varying proportions. Besides children's music (which includes four fairytale operas as well as the aforementioned songs), three other special categories of compositions stand out among his works: (1) pieces inspired by and dedicated to the Comtesse de Mercy-Argenteau (whom the composer knew from 1885 to her death in 1890; (2) works associated with the Circle of Russian Music Lovers (the "Kerzin Circle"); and (3) pieces inspired by the Russo-Japanese War and World War I.