“One is Christian or Jewish, not both.”

So says the chief rabbi of Paris in “The Jewish Cardinal” (2013), Israeli-born filmmaker Ilan Duran Cohen’s biopic about Cardinal Jean-Marie Lustiger (Laurent Lucas) — a Jewish convert to Catholicism who insisted on religious dual citizenship, embracing Catholicism without rejecting Judaism. “The Jewish Cardinal” is available via Amazon Instant Video and DVD.

For many people, it’s not as simple as the chief rabbi suggests. This week Rosh Hashana is being celebrated in many households that will also celebrate Christmas later this year; and while the children of many of these households have a clear sense of religious identity, others don’t. Blended religious heritages — whether due to mixed marriages, conversions, or just cafeteria-style syncretism — are more common today than ever.

“The Jewish Cardinal” is one of a pair of recent films that looks at Jewish/Catholic identity in the shadow of the Holocaust. The other, Pawel Pawlikowski’s award-winning film “Ida” (2013), is newly available on Amazon Instant Video and Blu-ray/DVD.

“Ida” tells a story of a young girl (Agata Trzebuchowska) orphaned by the Holocaust who has grown up in a Polish convent believing herself Catholic, unaware of her Jewish heritage or even her birth name. (While “Ida”’s protagonist is fictional, she has real-world counterparts; R.D. Rosen’s new book “Such Good Girls: The Journey of the Holocaust’s Hidden Child Survivors” recounts the true stories of three survivors, two with notable parallels to “Ida.”)

When we meet Ida — or Anna — she is a Franciscan novice preparing for final vows, and whether or not she will ultimately take them remains in doubt for at least much of the movie.

A third film about Jewish/Catholic identity dramatizes the true story of a renowned Jewish woman, now a Catholic saint, who did take vows as a Carmelite nun before dying in Auschwitz: Hungarian director Márta Mészáros’s “Edith Stein: The Seventh Chamber” (1995), available on DVD from Ignatius Press.

In each of these films, the protagonist’s identification with Catholicism is challenged by Jewish (and sometimes Catholic) interlocutors, including family members. Lustiger’s father and Stein’s mother bitterly oppose the conversion of their offspring, which they consider a betrayal. As for Ida, she learns the truth of her heritage from her aunt, a world-weary former state prosecutor who has lost her own faith.

Both “The Jewish Cardinal” and “Ida” have been hits at Jewish film festivals. “The Seventh Chamber” (starring Jewish actress Maia Morgenstern, who went on to play the Virgin Mary in “The Passion of the Christ”) debuted at the Venice Film Festival in 1995, where the International Catholic Organization for Cinema (OCIC, now SIGNIS) awarded it their annual OCIC Prize given to films “enhancing human values.” In our pluralistic society, the value of these films lies as much in the questions they raise as in whatever answers (if any) their characters come to.

Of the three, “The Jewish Cardinal” is the most accessible and direct in its story and themes. “Ida” is narratively straightforward, though its art-house reserve and severe aesthetic (filmed in black and white, with almost entirely static shots framing actors in the lower part of the screen) aren’t everyone’s cup of tea. “The Seventh Chamber” is the most difficult, with surreal, expressionist flourishes blending memory and symbolism. (A booklet with my essay exploring the structure and themes of “The Seventh Chamber” is included with the Ignatius Press DVD.)