The crucifixion scene had to be re-shot because a preview audience was offended at Jesus having a hairy chest.
Jeffrey Hunter and Robert Ryan's car broke down on the way to the "Sermon on the Mount" scene. In costume as Jesus Christ and John the Baptist, they had to push the car to get it started.
After its theatrical run, the film wasn't sold to the major networks, but instead went to local television stations. Because all television screens were approximately square at the time, those stations aired it in the pan/scan format, with approximately half of the wide screen picture cropped off, thus destroying the composition of the image. To date, the film has still not been shown by NBC, ABC, or CBS -- only by local affiliates of the three networks, and on cable television. As of 2017, it's in the Turner Classic Movies library, which has restored it to its original wide screen format and shows it in its correct original 70MM Technirama wide screen ratio, most often at either Christmas or Easter time, or both.
Franz Planer, the original director of photography, suffered a heatstroke during principal photography of the Sermon on the Mount sequence in Spain. This became one of his last films and he passed away only a few years later.