Sigismond Thalberg (Geneva, Switzerland, January 7, 1812–Posilipo, Naples, Italy, April 27, 1871) was a virtuoso pianist and composer. He was the illegitimate son of Count Moritz Dietrichstein and a Ms. Fortunée Stein. Stories were later circulated - perhaps to reinforce his aristocratic demeanour - that his mother was the Viennese Baroness Wetzlar. He studied under Simon Sechter, Carl Czerny and Johann Nepomuk Hummel.