See Mormon Film: Key Films of the Second Wave
This is one of the most momentous theatrical films ever made on Latter-day Saints, made completely independently by Twentieth-Century Fox but with close collaboration with The Church of Jesus Christ of Latter-day Saints, including Elder George Pyper serving as an on-set advisor to the film and close correspondence between producer Daryl Zanuck and Church President Heber J. Grant. After a private screening President Grant praised the film and its makers, calling it a magnificent day for the Church. Its Salt Lake City premiere included an official holiday--Brigham Young Day--and required seven theaters for the largest premiere in Hollywood history to that point. Many Latter-day Saints have since derided the film for its romantic subplot and depiction of Young as doubting his divine calling, but after decades of brutal cinematic misrepresentations the Church members of 1940 saw it as a major victory, and indeed it helped pave the way for the more positive and accurate portrayals that have appeared since.