I've gotten into fierce arguments with other people about this, so I'm looking for more input.
It comes down to what I remember vs what other people say really happened.
Turn on any DVD or even VHS cassette of Star Wars (the first movie released in 1977) and the first words you'll see in the opening crawl are "EPISODE IV: A NEW HOPE" or something similar.
But I too was 9 years old in 1977, and I saw Star Wars in the theater, and there was no mention of a fourth episode. The opening scene was just "STAR WARS". I distinctly recall the odd numbering of movies didn't occur until The Empire Strikes Back, in which the opening crawl displayed "EPISODE V". I remember movie critics having to explain why the second Star Wars movie was labeled number five. It was only then that the notion of three trilogies was floated. My schoolmates and I debated endlessly about how the first and third trilogy would play out. We even spun silly theories such as the children of Harrison Ford and Carrie Fisher playing the kids of Han Solo and Leia Organa.
But like I said, people have sworn up and down that in May of 1977, audiences everywhere saw "EPISODE IV: A NEW HOPE" and no on batted an eye. Which makes zero sense to me. Star Wars was the first Star Wars movie, and no one--George Lucas included--knew that it was going to be the smash hit that it was. Reportedly he rewrote plot points on the theory that the first movie would be a dud and no more would ever be made.
So am I completely out of my head? Please explain why the first major movie created by a guy almost no one had heard of would begin calling itself Episode IV.
You are right. There was no Episode IV on the opening crawl in the original release in May 1977. However, I remember hearing shortly after the release of SW that George Lucas had in mind a nine episode series (though it wasn't fully fleshed out at that time), and he decided to start with the fourth, as it seemed like the "most filmable" episode at the time, IIRC. Of course, when it became a huge hit, he realized he could continue the saga, so he began numbering the episodes. I remember hearing a lot of things about the series very early on that seemed to have panned out, weirdly enough. I also remember hearing a rumor that Darth Vader wore a mask because he was severely injured from contact with molten lava. Not sure where I heard that...must have been a fan magazine or something as this was long before the WWW days.
There are a lot of documentaries about the early scripts of Star Wars. Han Solo was supposed to be some sort of reptilian at one time, and Luke's last name was Starkiller instead of Skywalker. Also, I think Luke was supposed to be a dwarf once too. Its all very weird.