Such knowledge was often repressed due to the trauma inflicted by the Hitler era and anti-Semitic persecution during the communist decades that followed.

Poland, for centuries a refuge for Jews in a largely hostile Europe, once was home to Europe's largest Jewish population. Many Jews became culturally assimilated before World War II, while some sought survival through baptism during the German occupation of 1939-1945.

The discovery of Jewish roots is a growing phenomenon in Poland, where increasing numbers of Catholic or secular Poles in recent years have learned, often from deathbed confessions of loved ones or from chance discoveries of documents, that they are of Jewish descent.

Grodzka-Guzkowska knew Catholic prayers and customs so well that the anti-Nazi resistance tasked her with teaching them to Jews. Today, at age 86, she's living out her last years waiting to be buried in a white shroud according to the ancient customs of her ancestors.

"I remember running with children through the city. It was horrible," the now frail Grodzka-Guzkowska told The Associated Press, her hand trembling as she sat in a wheelchair.

Decades after she helped save the rabbi and about a dozen others, mostly children, by teaching them Christian customs, Grodzka-Guzkowska discovered documents in an old suitcase showing that her father and other close family members were Jews. Growing up she knew vaguely that one of her great grandmothers was Jewish but nothing more about those roots.

Magdalena Grodzka-Guzkowska's journey of self-discovery is pieced together from interviews with her and people close to her, emails made available to The Associated Press, information provided by Yad Vashem, her memoir "Lucky Woman," and documentary footage.

What she did not know back then: She was a Jew herself.

It was 1943 in Nazi-occupied Poland and any mistake could cost him his life, and hers, too. The Nazis would have killed her for helping a Jew.

"You've already exposed yourself! You're dead already!" the teenager whispered in his ear, and showed him how to perform the sacred gestures the way she and other Catholics did, so quickly and automatically that she barely touched her head and chest.

The rabbi, his newly shaven beard leaving his cheeks white, approached the lesson with gravity, skimming the water in the church font and crossing himself with slow reverence, hoping this would help him pass as Catholic.

WARSAW, Poland—As Nazi troops imposed their terror on Warsaw, an 18-year-old Polish girl slipped into a Warsaw church with an elderly rabbi to teach him how to dip his hand in holy water and cross himself.

Today, as democracy here matures, many Poles who discover their Jewishness have turned from hiding their Jewish roots to celebrating them, and non-Jews also are finding themselves drawn to the rich Polish-Jewish past.

For Grodzka-Guzkowska, a true understanding of her identity, and the danger it could have posed, came late in life. It inspired her to immerse herself in the Torah, dream of visiting Israel and ask Poland's chief rabbi to bury her in Warsaw's Jewish cemetery.

Like many Jews in prewar Poland, Grodzka-Guzkowska's Jewish great-grandmother, a pediatrician, intermarried. Her descendants were so well integrated into Catholic society that the matriarch's Jewishness meant little to Grodzka-Guzkowska when she was growing up.

"The most important fact about my great-grandmother was that she was a doctor, not a Jew," Grodzka-Guzkowska said in 2007 in an interview for a documentary in progress, "I am a Jew," by filmmakers Slawomir Grunberg and Katka Reszke.

"During the war I saved Jewish children while not being aware that I was Jewish," she recalled. "I saved them because that is what had to be done."

One landmark on her path to a new identity came during a dinner at the home of a Jewish friend in the 1990s, when she mentioned her Jewish great-grandmother -- her mother's mother's mother.

The friend, Konstanty Gebert, explained to her that this precise lineage was significant because Jewish law traces Judaism from mother to child, meaning that technically speaking, she was Jewish, too.

"This means that instead of saving those children, I should have been protecting myself?" Gebert recalled her saying. The realization made her giggle like a teenager.

After that evening, she began to cultivate a relationship with Warsaw's Jewish community and to attend services at Warsaw's Nozyk synagogue.

It was another discovery five years ago that confirmed her sense of Jewishness completely: the discovery of documents showing that her father was Jewish. Grodzka-Guzkowska had grown up attending a private Catholic school for girls, and her father's parentage had never been discussed in the family.

As she was sorting out old stuff cluttering a closet, she found identity documents in a suitcase that showed both her paternal grandparents were Jewish. This revelation, more than anything, caused a profound shift in her identity and made her finally think of herself as a Jew.

She learned a few Hebrew words and delved into reading the Old Testament. She envisioned herself wrapped in a simple white shroud with mourners placing stones on her tomb, rather than the flowers found in Catholic cemeteries.

"I will be buried in the Jewish cemetery as a Jew," she said. Chief Rabbi Michael Schudrich confirms her wishes will be carried out.