Because if 4 1 was first, the others wouldn’t have been made?
edit to strike 4
English: Jane will go to the store.
German : Jane will to the store go.
Arabic : To the store Jane will go.
Yoda: Go to the store, Jane will. Confront the Dark Side there, she must.
Real answer - it was a homage to sci-fi serials from back in the day, and to make it look like it was part of a bigger story.
Though later Lucas said he had an outline of 9 movies, and took the middle part to tell first. By outline I think he wrote “I should make 9 movies.” because there was very little in the prequels that had the same feel as the originals and the story of the prequels was way too disjointed and contrived.
Also, better Yoda joke:
Where there are Whills, there are ways.
Have we not had this argument over on another thread? 
The story of the prequels may have many problems, but disjointed and contrived is not necessarily one of them. Except in the sense that all fiction is contrived…
I can well imagine that Lucas did have a vague idea about Luke, Leia, Han and their children in mind when he started, but may well have realised that he’d probably not be around long enough to see it made properly (and I’m pretty sure that the story Zahn gave us wasn’t really the one Lucas had in mind - and nor will the upcoming version.) But a story that is not only set decades later but is actually being filmed decades later with many of the same actors is quite cool. Richard Linklater, eat your heart out. 
I absolutely agree. The disjointedness and contrivance were utterly unnecessary, and all the more destructive for being so.
I really can’t see a way to defend the prequel. It was thematically disjointed, the characterization didn’t make sense, and the plot was riddled with contradictions. None of it made any sense.
It all built up to the “incredible” scene of Annikin (or whatever his name was) being incinerated. To provide an excuse for the Vader outfit. But unfortunately, in context, looking a bit stupid for falling for Kenobi’s strike. Bouncing around on inflatables on a lava river.
Gosh all so dramatic. Gosh all so naive.
They stitched so much rubbish together they certainly (CERTAINLY!) had no time to actually watch the movies.
It was cereal box rubbish, through and through. Lucas didn’t care.
But I did. And I do. And I brought my children through the shame, clearly informing them of the lack of authenticity.
sigh
My mother went to see Star Wars in the theater not long after its release. When the scroll started, she thought “Crap, I missed the first three? This won’t make any sense.”
Have you read any of the early scripts for “The Star Wars” that are floating around? They bore even less resemblance to the original trilogy as filmed than the prequels do.
I watched that bit and thought “imagine how differently things would have gone if Obi-Wan had mercifully finished off his former friend instead of leaving him to slowly die in agony as his skin melted off.”
But 4 was first and the others were made.
If she saw “Episode IV” in the crawl for Star Wars, she didn’t see it “not long after its release.” That wasn’t added until a year after The Empire Strikes Back came out.
Funny joke, this is.
Well, if so, he didn’t clue Alan Dean Foster in on this. Foster wrote the first Star Wars spin-off novel* Splinter of the Mind’s Eye, in which Luke has rather romantic feelings towards Leia. This book came out between the first two movies, so it would seem that Lucas hadn’t worked out the whole family relations that early on.
*Foster also wrote the original film’s novelization although George Lucas got the credit on the cover.
