Simplify the following text for a Grade 11 native English-speaking person.
Original: Claudio Arrau LeÃ n ( February 6 , 1903-June 9 , 1991 ) was a Chilean-American pianist known for his interpretations of a vast repertoire spanning from the baroque to 20th-century composers , especially Beethoven , Schubert , Chopin , Schumann , Liszt , Brahms and Debussy . He is widely considered one of the greatest pianists of the twentieth century .
Simplified: Claudio Arrau LeÃ n ( February 6 , 1903 - June 9 , 1991 ) was a Chilean classical pianist and one of the greatest classical pianists of the 20th century .