The earliest surviving version of the popular Valse-Impromptu was written by Liszt into the diary of Tsaritsa Aleksandra Feodorovna on his visit to St Petersburg in 1842. This version appeared in print the following year as Petit valse favorite. On his next visit to Russia, in 1843, Liszt wrote a musically and technically more demanding version for Countess Marie Kalergis, a pupil of Chopin, but this was never published in the composer's lifetime. A final version, similar in shaping to the secon...