Riead began exploring ideas for an inspirational and uplifting film just before the devastating terror attacks of September 11 , 2001 , forced a realization on him that would come to define his project . “ I did n’t know there was that kind of evil in this world until then , ” says Riead . “ The attacks really brought that home . " '' The Letters '' became a labor of love for Riead during the fourteen years it would take to produce the film . 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 . In her letters , some of which have been published in the 2007 book '' Mother Teresa : Come Be My Light '' , Teresa revealed a profound spiritual suffering and emptiness experienced by some other saints , often referred to as a dark night of the soul . Riead read all of the letters that were available to the public and decided that they would make up the spine of his screenplay
devastating terror attacks of September 11 , 2001
September 11 attacks
The Letters (2014 film)