Ivan Yakovlevich Bilibin (1876 – 1942) was a Russian illustrator and stage designer who took part in the Mir iskusstva (“World of Art”), contributed to the Ballets Russes, co-founded the Union of Russian Artists, and from 1937 was a member of the Artists’ Union of the USSR. Ivan Bilibin gained popularity with his illustrations of Russian folk tales and Slavic folklore. Throughout his career he was inspired by the art and culture of medieval Russia
One of my favorite artists! Russia had a bunch of really cool fantasy painters / illustrators during that time, another one (a little earlier) I love is Viktor Vasnetsov: https://en.wikipedia.org/wiki/Viktor_Vasnetsov