A New York Times feature on new research into the geneaology of Cardinal John O'Connor, the New York City archbishop who died in 2000, makes the case that the influential Catholic figure's mother was born Jewish—which, according to one tradition by which Jewish heritage is passed down, means Cardinal O'Connor could also be considered Jewish.
“The basic fact is, my mother was Jewish,” said Mary O’Connor Ward-Donegan, the cardinal’s 87-year-old sister. Observing the Jewish matrilineal tradition, she added, “That means my two brothers were Jewish, my sister was Jewish and I am Jewish. Of that I am very proud.”
When he was alive, O'Connor knew that his mother had converted to Catholicism during her life, but doesn't seem to have known any more about her background. (O'Connor's mother booked it out of her Jewish community in Bridgeport, Connecticut to Philadelphia in her early adulthood and converted soon after.) American history geeks are advised to read the entire winding story of immigration and assmiliation.