The film is told through personal letters she wrote over the last forty years of her life and reveal a troubled and vulnerable woman who grew to feel an isolation and an abandonment by God.

The turning point for Riead was the discovery of a startling cache of heartfelt, formerly confidential letters written by Mother Teresa to her spiritual advisor, the Belgian Jesuit priest Celeste van Exem, over a nearly 50-year correspondence.

To play her confessor, Father van Exem, Riead cast Max von Sydow, the Swedish star who has been a favorite of directors ranging from Ingmar Bergman to Martin Scorsese.

He showed up and knew exactly what to do.” To portray the sisters and students of the Loreto Convent, the Bishop of Calcutta, Mother Teresa’s wealthy benefactors, and the residents of the poverty stricken slums, Riead cast professional actors from India’s Bollywood film industry, considered the largest in the world.

The scenes featuring Max von Sydow and Rutger Hauer (as van Exem’s confidant, Father Benjamin Praagh), were shot in a 15th-century London monastery.

The website's consensus reads: "The Letters tries to honor Mother Teresa with an unstintingly positive portrayal of her life and works, but ends up smothering a fascinating real-life story under a bland hagiography.

Opting for dutiful, reverent beatification over flesh-and-blood characterizations (or insights), the film is merely a clunky primer on how poor storytelling can make even the grandest of figures seem small — a fact that’s true with regard to Teresa as well as von Sydow, in a monotonous, creaky performance best left off his resume.

Not a trace of doubt or existential despair comes across in scenes of the nun’s life, and the script doesn’t even dip into those letters (a collection of which was published years ago) to let us hear of it in her own words.