Flash Gordon

George Lucas originally wanted to make a Flash Gordon movie in the 1970s. When he couldn't acquire the rights from King Features, he decided to write his own original space opera instead, directly resulting in Star Wars. Cloud City (inspired by the Hawkmen's Sky City) and the structural opening crawls are direct nods to Flash Gordon.

Alex Raymond's strip began in 1934 as King Features' answer to Buck Rogers, and the template it reached for was Burroughs's:

• An Earthman stranded on an alien world who becomes its champion
• A princess of that world as the romantic centre
• Warring races, court intrigue and a tyrant, all settled by swordplay rather than by the advanced technology the setting obviously has

That last point is the signature of the form. Planetary romance keeps the sword in a world with airships, and Burroughs is where the convention comes from. Flash Gordon then carries it forward to Lucas, which the graph already holds.