George Lucas

Lucas wrote the script for the original Star Wars and then took a long semi-hiatus from screenwriting. During that time, he came up with several story ideas and concepts. These include the Star Wars sequels, the Indiana Jones films, and Willow. But while he devised the story, the task of writing it would go to others.

For example, Lawrence Kasdan co-wrote The Empire Strikes Back, Raiders of the Lost Ark, and Return of the Jedi with Lucas and other storytellers. Willard Huyck and Gloria Katz wrote the screenplay for Indiana Jones and the Temple of Doom while Bob Dolman wrote Willow. All of these films originated as original story ideas thought up by Lucas.

To be clear, this isn't to say that Lucas never put pen to paper. Hollywood scripts undergo multiple rewrites, revisions, and reimaginings at the hands of many creative types, from writers to directors to producers, and these extra-narrative scribes seldom receive a screenplay credit. We're simply saying that after A New Hope, Lucas didn't take a story from concept to script as a sole endeavor.

And that changed with The Phantom Menace.

Space Echo

We see two main principles guiding Lucas' script. The first, and most obvious, is to tell the story of Anakin Skywalker's fall from the light side of the Force and his transformation into Darth Vader—although he jumped super far back in the timeline, meaning Anakin is more rambunctious squirt than imposing Dark Lord.

The second principle is to have the script "echo" the original trilogy, especially A New Hope. While explaining this goal to the film crew, Lucas said he designed it to be "like poetry. They rhyme. Every stanza kind of rhymes with the last one." (Source)

And you can see this resonance throughout. Anakin's desire to leave Tatooine and become a Jedi mirrors Luke's origin story. Likewise, Padmé's story of a young damsel in distress who grows into a leadership role shares many parallels with Leia's. And the mentor characters of both films, Qui-Gon and old Obi-Wan, are killed by Sith warriors, leaving their young apprentices, young Obi-Wan and Luke respectively, to take up the fight.

But the film isn't a retread. Lucas added many new elements to the Star Wars formula, including politics, the inner workings of Jedi society, and large-scale battles between opposing armies. He would continue to explore all of these in the scripts of the other two prequel films.