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.
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.
"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.
"Without respect?" the rabbi asked.
"Without any respect!" the girl replied.
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.
What she did not know back then: She was a Jew herself.
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.
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.
Shared humanity, not ancestry, impelled her to heroism.
"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.
"And I felt I had to help."
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.
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.
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.
Such knowledge was often repressed due to the trauma inflicted by the Hitler era and anti-Semitic persecution during the communist decades that followed.
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.
Grodzka-Guzkowska's gradual embrace of Judaism paralleled cultural shifts within Poland after the 1989 collapse of its communist government, as it began its painful but ultimately successful transition to democracy.
These days, although there is occasional vandalism of Jewish cemeteries and some anti-Semitism persists, Polish Jews sometimes say they feel safer walking the streets of Warsaw in a yarmulke, or skullcap, than they would in many Western European cities.
As Poles with Jewish roots feel freer to explore a heritage that once spelled death, the nation's Jewish traditions also are going mainstream, with students packing Jewish history and Hebrew courses and all kinds of people flocking to Jewish festivals held in Krakow, Warsaw and even in smaller towns.
In 1939 Poland's Jews numbered nearly 3.5 million, about 10 percent of the population. Today, there are no firm statistics on how many people in this nation of 38 million identify themselves as Jewish. The Conference of European Rabbis estimates that Poland's Jewish population has grown from just a few thousand to more than 20,000 over the past 30 years.
Many of the prewar Jews were traditional Orthodox believers who lived in villages or shtetls that formed the archetypal image made famous in "Fiddler On The Roof." Many others became fully integrated into mainstream Polish society: doctors, writers, military officers, scientists.
Amid Poland's cultural changes, aging Poles with family secrets feel it is finally time to pass them on to the next generation. In some cases, such discoveries spark personal transformations, inspiring adult men to undergo circumcision or to take on new names.
Most of those who decide to live as Jews are in their 20s or 30s, with the older generations often still too fearful of anti-Semitism to want to live openly as Jews. Grodzka-Guzkowska is a prominent exception.
"It's an amazing story," said Rabbi Stas Wojciechowicz. "Three generations after the war people are rediscovering their Judaism and some are undergoing formal conversion. ... It's the third and fourth generation that is closing this cycle."
He said he also has been struck by how so many Polish Jews belong very much to the Jewish and Catholic worlds simultaneously. His synagogue, for instance, practically empties of worshippers around Christmas and All Saints Day, a major Catholic holiday when Poles visit the graves of ancestors.
"They say they are sorry but they need to be with their parents at those times," he said. "Almost everybody has this story of a divided family, with one part Jewish _ mostly the younger generation _ while the older one isn't."
Not long after Grodzka-Guzkowska embraced her Jewishness, it proved an obstacle to her being honored for her wartime heroism.
A Jewish boy she had rescued was reunited with her in 2007 as a grown man. William Donat petitioned Israel's Yad Vashem Holocaust memorial to name her a "Righteous Among the Nations" in recognition of her wartime heroism.
But Yad Vashem hesitated on the grounds the award only recognizes non-Jews.
As Yad Vashem wavered, Chief Rabbi Schudrich and her friend Gebert, a prominent member of Warsaw's Jewish community, made the case that she should be given the award because she had acted during the war with the consciousness of a Catholic, not a Jew.
"Magda decided in a moment to save Jewish children," Schudrich wrote in a 2008 email to Yad Vashem. "Why are we taking so long?"
The Jerusalem-based institute ultimately ruled in her favor: It honored her in 2009.
Vanessa Gera can be reached at http://twitter.com/VanessaGera