was a German cellist and composer who worked for around 20 years as a professor at the Moscow Conservatory.
Fitzenhagen was the son of the municipal music director of Seesen and received instrumental lessons at an early age, first piano at the age of five, cello at the age of eight and violin at the age of eleven. At the age of eleven he made his public debut as a cellist. In 1862 he became a student of Theodor August Müller. The Duke of Brunswick released him from military service. Patrons made it possible for him to study with Friedrich Grützmacher in Dresden in 1867. A year later he became a soloist in the Dresden court orchestra. In 1870 he accepted an offer from Nikolai Rubinstein as a professor at the newly founded Moscow Conservatory, although Franz Liszt tried to engage him as principal cellist at the Grand Ducal Orchestra in Weimar.
In Russia Fitzenhagen gained a reputation as an important teacher, soloist and chamber musician. His students included Joseph Adamowski and Anatoly Brandukov. He was appointed concertmaster of the Russian Imperial Music Society and in 1884 director of the Moscow Music and Orchestra Society. He was friends with Tchaikovsky and took part in the world premieres of several of his chamber music works, e.g. the Piano Trio op. 50. In 1876 Tchaikovsky dedicated his Rococo Variations op. 33 to him. Before the premiere in 1877, which he played himself, Fitzenhagen made considerable changes to the order, among other things, and discarded one variation entirely. In this modified form, which Tchaikovsky sanctioned after initial protest, the Variations were also published in 1889 and are often played to this day.
Fitzenhagen left more than 60 compositions, including 4 concertos for cello and orchestra and a suite for cello and orchestra, as well as chamber music (including a string quartet, perpetuum mobile op. 24 for cello and piano) and songs.
