I reread a portion of Lucia's memoirs after seeing the movie and found lines that were directly incorporated into the script. Obviously, Ian and Dominic Higgins the producers, directors, and scriptwriters for the film, as well as the main catalyst for everything else, had great respect for the story and wanted to portray it accurately. In an interview on The 13th Day website, Ian pointed this out saying:
The 13th Day is a dramatization of actual events and most of the characters that appear in the film actually existed, so research was crucial from that point of view and from day one, everyone on the team was committed to realizing this film in such a way that it kept as true to the actual events as possible. As filmmakers we’re also very big believers in the value of research as inspiration too. We’ve found so many great ideas for a scene, hiding away in the pages of an old book while researching the script. It’s like digging for gold, there are so many fantastic nuggets of information buried away, just waiting to be re-discovered, it’s a really exciting part of the process.If you have wondered about Fatima and what happened there, you don't want to miss this movie. It would make a great addition to any Catholic familiy's film library giving a glimpse into extraordinary events that occasionally happen to ordinary people. I found it an inspiration to the soul and satisfying proof that it doesn't take big bucks to tell a great story. This was the first feature-length film from this talented pair which gives one great hope for the future. Hollywood no longer has a stranglehold on the industry, praise God. I highly recommend The 13th Day!