John Bayley (circa 1847 – 1910) was an English bandmaster, clarinetist, violinist, and organist who was active in his native country and North America.
 Cornetist Herbert L. Clarke described him in his autobiography as "a finished musician of high order; he was a remarkable organist... and one of the best clarinetists I have ever heard in my life."
"The Saddest Song I Ever Heard" is the title of a R&B single by For Real.
 Written by Diane Warren.
 "The Saddest Song I Ever Heard" spent eight weeks on the US singles chart.
 The song would be covered two years later by Australian girl group Cherry.
 Their version, released with the shortened title "Saddest Song", peaked at #46 in Australia.
Ennio Bolognini (November 7, 1893—July 31, 1979) was an Argentine-born American cellist, guitarist, composer, conductor, professional boxer, pilot, and flight instructor.
 Though seldom remembered today, during his lifetime his musical virtuosity was widely admired by his contemporaries.
 Pablo Casals praised him as "the greatest cello talent I ever heard in my life", and Gregor Piatigorsky told Christine Walevska's father, "No, I am not the greatest cellist in the world; neither is Feuermann.
 The greatest is the Argentine Bolognini!"
 (A similar quote has been elsewhere misattributed to Emanuel Feuermann)
Jascha Spivakovsky (18 August 1896 – 23 March 1970) was a Ukrainian-Australian piano virtuoso of the 20th century.
 He was hailed as a child prodigy in Odessa but almost murdered by Imperial Guards during the 1905 Pogrom.
 He fled to Berlin and was declared the heir of Anton Rubinstein and likened to Ignacy Paderewski and Teresa Carreño before being imprisoned as an Imperial Russian enemy alien during World War I.
 In the interwar period he became internationally recognized as one of the greatest pianists in the world and regarded in Europe as the finest living interpreter of Brahms.
 He also formed a trio which toured Europe with phenomenal success and was declared the finest in the world.
 Towards the beginning of 1933 he was warned by Richard Strauss in a musically-coded secret message that he had become a Nazi target due to his Jewish heritage.
 He fled to Australia a few days before the Nazi seizure of power and put his musical career on hold to help people escape the Third Reich.
 After World War II he returned to the stage and astounded the toughest of critics with the power, depth and maturity of his interpretations.
 Although his fame dimmed after he ceased touring because he had made no commercial (solo) studio recordings, his rediscovery was sparked in 2015 by the first releases of his live performances.
 These have caused considerable excitement among music lovers and prompted some experts to declare Spivakovsky one of the greatest pianists they have ever heard.
Cognicide is Western Addiction's first full-length album.
 It was released on Fat Wreck Chords on November 1, 2005.
 The album is known for featuring a sound heavily inspired by Hardcore punk acts of the 1980's.
 Fat Mike has often listed Cognicide as one of the greatest releases on his label, Fat Wreck Chords, calling it one of the best hardcore albums he's ever heard.
 Joey Cape of Lagwagon has also stated that it is his favorite album released on Fat Wreck Chords.
Jascha Heifetz ( ; 2 February [O.S. 20 January] 1901 10 December 1987) was a Lithuanian-born Russian violinist.
 Many consider him to be the greatest violinist of all time.
 Born in Vilna, he moved as a teenager to the United States, where his Carnegie Hall debut was rapturously received.
 He was a virtuoso since childhood—Fritz Kreisler, another leading violinist of the twentieth century, said on hearing Heifetz's debut, "We might as well take our fiddles and break them across our knees."
Joshua Altheimer (May 17, 1910 – November 18, 1940) was an American pianist who is remembered for accompanying Big Bill Broonzy, Lonnie Johnson, Sonny Boy Williamson and others on influential blues recordings made in Chicago in the 1930s.
 He was described by Broonzy as "the best blues piano player I ever heard", and by blues historian Hugues Panassié as "the greatest blues pianist on records".
3 Feet High and Rising is the debut studio album by American hip hop trio De La Soul.
 It was released on March 14, 1989, by Tommy Boy Records.
 It marked the first of three full-length collaborations with producer Prince Paul, which would become the critical and commercial peak of both parties.
 It is consistently placed on 'greatest albums' lists by noted music critics and publications.
 Robert Christgau called the record "unlike any rap album you or anybody else has ever heard."
 In 1998, the album was selected as one of "The Source Magazine's 100 Best Rap Albums."
John Robert Lee Bradley (October 5, 1919 – May 3, 2007) was an American gospel music singer.
 He was the favorite singer of the Rev. Dr. Martin Luther King Jr. and was nicknamed "Mr. Baptist."
 Mahalia Jackson once said he had the greatest voice she had ever heard, stating "Nobody need mess with 'Amazing Grace' after Bradley gets through with it."
Grigoraș Ionică Dinicu (] ; April 3, 1889 – March 28, 1949) was a Romanian violin virtuoso and composer.
 He is most famous for his often-played virtuoso violin showpiece "Hora staccato" (1906) and for making popular the tune Ciocârlia, composed by his grandfather Angheluș Dinicu for "nai" (the Romanian pan flute).
 It is rumored that Jascha Heifetz once said that Grigoraș Dinicu was the greatest violinist he had ever heard.
 In the 1930s he was involved in the political movement of the Romanian Roma and was made honorary president of the "General Union of the Romanian Roma".
 Other well known compositions are: "Hora mărțișorului" ("Mărțișor", literally "little March", is a major Romanian seasonal holiday on March 1st), "Ceasornicul" ("The Clock") and "Căruța poștei" ("The Post Wagon").

Question: Who is the greatest violinist ever heard by the greatest violinist of all time?
Answer: Grigoraș Dinicu