and authenticity of individual works. Instruments Although some of Mozart's early pieces were written for harpsichord, he also became acquainted in his early years with pianos made by Regensburg builder . Later when Mozart was visiting Augsburg, he was impressed by Stein pianos and shared this in a letter to his father. On 22 October 1777, Mozart had premiered his triple-piano concerto, K. 242, on instruments provided by Stein. The Augsburg Cathedral organist Demmler was playing the first, Mozart the second and Stein the third part. In 1783 when living in Vienna he purchased an instrument by Walter. Leopold Mozart confirmed the attachment which Mozart had with his Walter fortepiano: "It is impossible to describe the hustle and bustle. Your brother's pianoforte has been moved at least twelve times from his house to the theatre or to someone else's house." Influence His most famous pupil, whom the Mozarts took into their Vienna home for two years as a child, was probably Johann Nepomuk Hummel, a transitional figure between the Classical and Romantic eras. More important is the influence Mozart had on composers of later generations. Ever since the surge in his reputation after his death, studying his scores has been a standard part of classical musicians' training. Ludwig van Beethoven, Mozart's junior by fifteen years, was deeply influenced by his work, with which he was acquainted as a teenager. He is thought to have performed Mozart's operas while playing in the court orchestra at Bonn and travelled to Vienna in 1787 hoping to study with the older composer. Some of Beethoven's works have direct models in comparable works by Mozart, and he wrote cadenzas (WoO 58) to Mozart's D minor piano concerto K. 466. Composers have paid homage to Mozart by writing sets of variations on his themes. Beethoven wrote four such sets (Op. 66, WoO 28, WoO 40, WoO 46). Others include Fernando Sor's Introduction and Variations on a Theme by Mozart (1821), Mikhail Glinka's Variations on a Theme from Mozart's Opera The Magic Flute (1822), Frédéric Chopin's Variations on "Là ci darem la mano" from Don Giovanni (1827), and Max Reger's Variations and Fugue on a Theme by Mozart (1914), based on the variation theme in the piano sonata K. 331. Pyotr Ilyich Tchaikovsky, who revered Mozart, wrote his Orchestral Suite No. 4 in G, Mozartiana (1887), as a tribute to him. References Notes Citations Sources Further reading