John Cardinal O’Connor and Mayor Edward Koch turn out with thousands of others for the annual Puerto Rican Day Parade down Fifth Avenue in New York, on Sunday, June 11, 1989.(Mario Cabrera/AP)

When former New York City Mayor Ed Koch died in February 2013, he had a Jewish funeral at Temple Emanuel on Manhattan’s Upper East Side. He also, however, was memorialized in a Mass at St. Patrick’s the following month, a testament to his special appreciation of Catholicism and close friendship with John Cardinal O’Connor, the Archbishop of New York. Koch and O’Connor together wrote the book His Eminence and Hizzoner, and after O’Connor died in 2000, Koch kept the memorial card from the funeral on his desk.

Jonathan R. Cohen, a former advisor to Koch, wrote of the former mayor’s own Catholic send-off a decade later, recalling the friendship between the two leaders:

Of all his friends in the clergy, though, Koch was perhaps closest to John Cardinal O’Connor. The Mayor went to the Vatican with a large group of prominent New York Catholics to witness the pope’s elevation of the cardinal from archbishop in 1985. For his part, the cardinal became a strong defender of Israel and an active friend of the Jewish community, declaring that year that anti-Semitism is a sin.

While O’Connor’s connection to Koch is well-known, as is the Cardinal’s longstanding commitment to the Jewish community—he visited the Dachau concentration camp in 1975 and participated in the movement to free Soviet Jewry in the late 1980s—some rather surprising new information has been uncovered: O’Connor was halakhically Jewish. According to Catholic New York, genealogical research undertaken by O’Connor’s sister, Mary O’Connor Ward, reveals that their mother, Dorothy Gumple O’Connor, was born Jewish, and converted to Catholicism.

The fact that Mrs. O’Connor was Jewish by birth came to light during a genealogical search undertaken by Mrs. Ward at the prompting of one of her daughters, Eileen Ward Christian, who had begun digging into the family’s history. Mrs. Ward said in an interview that when she was growing up she surmised that her mother was a convert, but that the family never discussed the matter.

Asked whether Cardinal O’Connor was aware of his Jewish lineage, she said, “I have no way of knowing that.” But she added, “I just don’t understand, if he knew, why something wouldn’t have come up before. He was so close to the Jewish community.”

That the Cardinal likely didn’t know of his own connection to Judaism seems all the more unusual given his involvement with the community. Still, his sister says, “I think he would have been very proud of it.”

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