After their widowed father died in 1995, jazz pianist Ted Rosenthal and his sister packed up the family home in Great Neck, LI. They didn’t know what that box of letters, all written in German, was doing in the attic, but Rosenthal took them home, anyway.
The letters stayed, nearly forgotten, until some 3-and-a-half years ago, when Rosenthal was invited to his grandmother’s hometown in Germany, where the local historical society rebuilt a Jewish school destroyed by the Nazis. Rosenthal asked a historian if he’d mind translating some of the letters. “Send them,” he was told.
The contents, once translated, blew his mind.
“It was unbelievable,” the Upper West Sider tells The Post. “I heard my grandmother’s voice, my aunt’s . . . I didn’t know any of those people!”
Rosenthal’s father, Erich, never spoke of them. In those 200 letters, written from 1938 to 1941, Erich’s mother, Herta, poured her heart out to him, her only child, who left Germany to study at the University of Chicago.
He was the only one in his immediate family to survive the Holocaust.
Now that family history is an opera. Rosenthal’s “Dear Erich” — scored for a string quartet, jazz trio, woodwinds, brass and the New York City Opera — plays through Sunday at the Museum of Jewish Heritage.
“I view it as a crossover piece,” says its 59-year-old composer. Not only is it a mix of genres — think soaring arias and bluesy horn solos — but it describes the journey taken by his father, who crossed the Atlantic toward freedom and a new life as a sociologist, Queens College professor and family man.
Rosenthal suspects that survivor’s guilt kept his father from speaking of the past. “He never knew what happened to his mother,” he says. “I’m sure that contributed to the pain he felt, but never discussed.”
The opera flits between past and present, Chicago and Germany. Some of the letters are typically motherly: Despite her hardships, Herta worries that her son isn’t eating enough.
One of the most heartbreaking missives followed the Nazi rampage Kristallnacht. Aware that her letters could be read by the authorities, Herta chose her words carefully.
“Your father had to take a trip with many friends and relatives,” she wrote. That was code, Rosenthal says, for “they were herded up and taken away.” There were no concentration camps yet, but Theodor Rosenthal eventually returned to his wife so broken, he died days later.
And Herta? Rosenthal’s wife, Lesley — an “Internet research wiz,” who co-wrote the opera’s libretto — found records showing a train from Herta’s town left on June 12, 1942, six months after her last letter. It went to the Sobibor death camp.
“In the opera, we can do a few things we can’t in real life,” says Rosenthal. “There’s a lost letter we made up where Erich does learn [about] his mother — and that she really wanted him to go forth with his life.”