 Under Balakirev's mentoring, Rimsky-Korsakov turned to other compositions.He began a symphony in B minor, but felt it too closely followed Beethoven's Ninth Symphony and abandoned it.He completed an Overture on Three Russian Themes, based on Balakirev's folksong overtures, as well as a Fantasia on Serbian Themes that was performed at a concert given for the delegates of the Slavonic Congress in 1867.