Mstislav Leopoldovich Rostropovich (Мстисла́в Леопо́льдович Ростропо́вич) (born March 27, 1927, Baku, USSR, died April 27, 2007, Moscow), affectionately known as Slava, was Russian and a naturalized American cellist and conductor, considered to be one of the greatest cellists ever. Rostropovich was born in Baku, Azerbaijan (then part of the Soviet Union). From 1943 to 1948, he studied at the Moscow Conservatory, where he became professor of cello in 1956.