Well, to make a long story short, Leonard Bernstein was Jewish!
Since Leonard Bernstein's mother was Jewish, and in Orthodox Judaism and Conservative Judaism, those with a Jewish mother (or those who underwent a halakhic conversion) are considered Jewish, then that makes him Jewish. His father was Jewish too.
Leonard Bernstein (whose full birth name was Louis Bernstein) was born on August 25, 1918 in Lawrence, Massachusetts. Leonard Bernstein passed away on October 14, 1990 (aged 72).
His fame derived from his long tenure as the music director of the New York Philharmonic, from his conducting of concerts with most of the world's leading orchestras, and from his music for West Side Story, as well as Candide, Wonderful Town, On the Town and his own Mass.
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