“What do the following have in common: Irving Berlin, George and Ira Gershwin, Richard Rodgers, Lorenz Hart, Oscar Hammerstein, Leonard Bernstein, Stephen Sondheim, the list goes on and on? Yes, they’re musical titans every one. And they also happen to be Jewish.”

So begins “Broadway Musicals: A Jewish Legacy,” a 90-minute documentary that you can watch at the link (the movie begins after the 8:40 mark.) First broadcast on PBS in 2013, the show feels like an appropriate gift for the Jewish new year, 5785.

Why were so many of Broadway songwriters in the twentieth century Jewish?

The documentary suggests several factors, as the documentary’s filmmaker Michael Kantor has explained: “It’s Yiddish theater, it’s Jewish liturgical music that feeds into great Broadway shows, it’s a Jewish ethos that says we’re not just going to amuse you but we’re going to instruct you: If you behave a certain way, you can get the girl, you can win. America is a place where that optimism will reign…These are children of immigrants who want to master the language….”

The film, narrated by Joel Grey, features interviews with dozens of composers (some — like John Kander, Stephen Schwartz, Marc Shaiman and Maury Yeston — at their piano), historians, critics, and relatives of the greats; as well as performances by David Hyde Pierce (Spamalot), Matthew Broderick and Kelli O’Hara (Nice Work if You Can Get It), Zero Mostel (Fiddler on the Roof), Betty Comden and Adolph Green (On the Town), Nathan Lane (The Producers), Al Jolson (Sinbad), Fanny Brice (The Great Ziegfeld), Barbra Streisand (Funny Girl), Grey himself (Cabaret), Dick Van Dyke (Bye Bye Birdie), Danny Kaye (Lady in the Dark), Ethel Merman (Gypsy.) It offers portraits of some of the best-known of the Jewish composers with some fascinating anecdotes.

We’re told that Cole Porter, the most obvious example of a successful Broadway composer who was not Jewish, told Richard Rodgers that the secret to his hits was that he had figured out how to write “Jewish tunes.”

Gershwin made his mission to incorporate blues, jazz and ragtime — Black music — into the mainstream Broadway musical. There was already an affinity between the Jewish and the African-American musical tradition; poet David Lehman points to the use in both traditions of the minor key. Indeed, for “Porgy and Bess,” the Gershwins adapted the music from a standard Hebrew prayer for use in “It Ain’t Necessarily So” — “To borrow a prayer over the Bible for a song that debunks the Bible seems to me to be the definition of chutzpah,” Lehman says.

A partial list of Jewish songwriters who had at least one show on Broadway