"Indiana Jones and the Last Crusade", the third film in the popular Indiana Jones series, went through a flimsy scripting process before Boam was hired to write a draft. As early as 1984, George Lucas was playing with the concept of having the fictional archeologist-adventurer encounter the fabled Holy Grail, the cup said to have been used by Jesus Christ during the Last Supper. Director Steven Spielberg rejected Lucas's script outlines, disliking the Grail idea. Screenwriter Diane Thomas wrote a haunted house story for Indiana Jones, but Spielberg said that after producing "Poltergeist", he didn't want to do a similar film. Lucas hired Chris Columbus to write a draft for the film, and he submitted "Indiana Jones and the Lost City of Sun Wu Kung", a story with evil spirits, ghosts, and demons. Again, Spielberg rejected the story as not believable enough. Lucas convinced him to go back to the Holy Grail idea, and Menno Meyjes was hired to develop another screenplay. The new script focused on the Arthurian legend aspect of the Holy Grail. Although the script was not to the liking of Lucas and Spielberg, it had elements that eventually became part of the finished film: the Holy Grail, and the introduction of Indiana Jones' father, Henry Jones Sr.