Question: How did Russian composer, Pyotr Ilyich Tchaikovsky describe Karl Davydov?

Context paragraphs:
Karl Davydov: Karl Yulievich Davydov (Russian: Карл Юльевич Давыдов ; 15 March [O.S. 3 March] 1838 26 February [O.S. 14 February] 1889 ) was a Russian cellist of great renown during his time, and described by Pyotr Ilyich Tchaikovsky as the "czar of cellists".  He was also a composer, mainly for the cello.

Symphony No. 2 (Rachmaninoff): Symphony No. 2 in E minor, Op. 27 is a symphony by the Russian composer Sergei Rachmaninoff, written in 1906–07.  The premiere was conducted by the composer himself in Saint Petersburg on 8 February 1908.  Its duration is approximately 60 minutes when performed uncut; cut performances can be as short as 35 minutes.  The score is dedicated to Sergei Taneyev, a Russian composer, teacher, theorist, author, and pupil of Pyotr Ilyich Tchaikovsky.  Alongside his Piano Concerto No. 2 and Piano Concerto No. 3, this symphony remains one of the composer's best known compositions.

Tchaikovsky (film): Tchaikovsky (Russian: Чайковский ) is a 1970 Soviet biopic film directed by Igor Talankin.  It featured Innokenty Smoktunovsky in the role of the famous Russian composer Pyotr Ilyich Tchaikovsky.  It was nominated for the 1971 Academy Award for Best Foreign Language Film as well as the Academy Award for Original Song Score and Adaptation.

Piano Sonata in G major (Tchaikovsky): The Grand Piano Sonata in G major, Op.  37, was written by Russian composer Pyotr Ilyich Tchaikovsky in 1878.  Though initially received with critical acclaim, the sonata has struggled to maintain a solid position in the modern repertoire.  Nevertheless, the sonata has been recorded numerous times and is recognized as one of the composer's masterworks.  It is dedicated to Karl Klindworth.

Pyotr Ilyich Tchaikovsky: Pyotr Ilyich Tchaikovsky ( ; Russian: Пётр Ильи́ч Чайко́вский ; 25 April/7 May 1840 – 25 October/6 November 1893), often anglicized as Peter Ilich Tchaikovsky, was a Russian composer of the romantic period, some of whose works are among the most popular music in the classical repertoire.  He was the first Russian composer whose music made a lasting impression internationally, bolstered by his appearances as a guest conductor in Europe and the United States.  Tchaikovsky was honored in 1884, by Emperor Alexander III, and awarded a lifetime pension.

Chaikovskij (crater): Chaikovskij (sometimes Tchaikovsky) is a crater on Mercury.  It has a diameter of 165 kilometers.  Its name was adopted by the International Astronomical Union in 1976.  Chaikovskij is named for the Russian composer Pyotr Ilyich Tchaikovsky, who lived from 1840 to 1893.

Swan Lake (1895): The 1917 Petipa/Ivanov/Drigo revival of Swan Lake is a famous version of the ballet "Swan Lake", (ru. " Лебединое Озеро"), (fr.  "Le Lac des Cygnes").  This is a ballet by Pyotr Ilyich Tchaikovsky based on an ancient German legend, presented in either four acts, four scenes (primarily outside Russia and Eastern Europe), three acts, four scenes (primarily in Russia and Eastern Europe) or, more rarely, in two acts, four scenes.  Originally choreographed by Julius Reisinger to the music of Pyotr Ilyich Tchaikovsky (opus 20), it was first presented as "The Lake of the Swans" by the Ballet of the Moscow Imperial Bolshoi Theatre on 20 February/4 March 1877 (Julian/Gregorian calendar dates) in Moscow, Russia.  Although the ballet is presented in many different versions, most ballet companies today base their stagings both choreographically and musically on this revival by Marius Petipa and Lev Ivanov, staged for the Imperial Ballet, first presented on 15 January/27 January 1895, at the Imperial Mariinsky Theatre in St. Petersburg, Russia instead of the original version.

Vladimir Davydov: Vladimir Davydov (December 14 [O.S. December 2] 1871 – December 27 [O.S. December 14] 1906 ) was the second son of Lev and Alexandra Davydov, and nephew of the composer Pyotr Ilyich Tchaikovsky, who called him "Bob".  Although Tchaikovsky was infatuated with him, and although both were homosexual, there is no evidence that their relationship ever became sexual in nature.

Kamarinskaya: Kamarinskaya (Russian: камаринская ) is a Russian traditional folk dance, which is mostly known today as the Russian composer Mikhail Glinka's composition of the same name.  Glinka's "Kamarinskaya", written in 1848, was the first orchestral work based entirely on Russian folk song and to use the compositional principles of that genre to dictate the form of the music.  It became a touchstone for the following generation of Russian composers ranging from the Western-oriented Pyotr Ilyich Tchaikovsky to the group of nationalists known collectively as The Five and was also lauded abroad, most notably by French composer Hector Berlioz.

International Tchaikovsky Competition: The International Tchaikovsky Competition is a classical-music competition held every four years in Moscow, Russia, for pianists, violinists, and cellists between 16 and 32 years of age, and singers between 19 and 32 years of age.  The competition is named after Russian composer Pyotr Ilyich Tchaikovsky and is an active member of the World Federation of International Music Competitions.

Supporting paragraphs: Karl Davydov Pyotr Ilyich Tchaikovsky
Answer: czar of cellists