When people write fanfictions about Sailor Moon, they often refer to the story before the story:
The "Silver Millennium"
Mostly, because it's so mysterious - this particular past seems to be such a touchy matter, the characters don't seem to like to talk about it a lot. Of course, this leaves a lot of room for imagination - the latter being basically fanfiction-world's home and origin.
But here's the thing: Though there's only few facts stated in all the Sailorverses, there's also quite some information given. Some is contradictory, some complementing.
In the following I tried to depict, what we know happened. Yet I don't claim this to be flawless.
So please, research yourself a bit, if you want to write your own Silver Millennium fanfic.
Of course, Bishoujo Senshi Sailor Moon, its characters and story and everything around and about it belong to Takeuchi Naoko, Toei Animation and other rich people. Please don't sue me.
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Once upon a time... ..there was a Moon Kingdom. On the Moon, yes. People lived there. Well, we don't know how many lived there - the background information is vague on that subject - but there lived at least some.
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| View from the Moon. |
It was an era loooong ago (the 'when' is also a mystery) and it was called the "Silver Millennium", which leads us to believe, it lasted for about 1,000 years, before it all went downhill. And, it did go up in flames pretty well.
But I am getting ahead of myself....
It was a happy, peaceful era... -or at least it was supposed to be that.
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| The Queen's magical Silver Crystal. |
So, in this castle lived a queen, named Queen Serenity. She was quite powerful. She owned the Silver Crystal. Which is... well, we don't know where it comes from or what exactly it is, but whoever has it, seems to be powerful.
Anyway, Queen Serenity ruled over the Moon, which watched over the earth, protecting the planet and its earthlings from bad things.
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| Daughter and mother Serenity. |
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| Princess Serenity |
They were not on their own. There were the so called Solar Sailor Senshi, female warriors (even back then in mini-skirts, which we assume are magical, hence provide better protection than regular armor), who... well, here the information gets vague. How old were these girls and were they to follow the Queen's orders or the Princess' because they were the young highness' bodyguards?
Well, for all we know, four of these guards (namely Mercury, Venus, Mars and Jupiter) were on the moon when bad things started happening.
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| Lovebirds~ |
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| Stalker Beryl |
At first, the teenage princess fell in love with a prince from Earth,
because Earth was such a pretty sight from the moon and also had royalties. And this one was particularly charming.
His name was Endymion.
That alone was not a bad thing, but Endymion had another fan.
A woman named Beryl also had her eyes set on the guy. So, one day
Beryl, being busy stalking unaware Endy, found him making out with the
Moon's princess - which she didn't take well.
Beryl ran away, cried a lot and then there was a meteor shower. She went to examine a crater and stumbled onto some magical being which called itself "Queen Metalia". The giant shadow-creature (later and weakened it rather resembled the inside of a lava-lamp) convinced grief-stricken, jealousy-driven Beryl, that freeing her and destroying the Moon Kingdom together was one awesome plan.
Because, the Princess had stolen her man, so the entire Moon had to go.
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| "Lava-lamp" Metalia |
Beryl helped Metalia, became very powerful, crowned herself Queen, even convinced (using dark magic) Prince Endy's bodyguards / generals to deceive him and join her force instead and one lovely day, while there was one big party on the Moon, they stroke.
(Needless to say, that this Metalia-blubb was a pretty dark and evil thing - and it had impacted on earth from space / the sun, did something dark and bad to the sun itself as well, as a result meaning: Moon failed to protect Earth from something bad >_> )
It might as well have been Princess Serenity's birthday ball, when Endy approached his beloved Princess not-so-secretly, asking for a dance. For some reason Endy wasn't very popular on the Moon at that time. Might have something to do with him being one of these Earthlings that recently seemed to be preparing something suspicious... (yet, everyone on the Moon was rather unprepared, it seems) Conveniently it was a masked ball~ ...that kinda got stuck with him though.
Anyhow, he swore to protect her, confessed his undying love... oh, and there might be some attack coming soon! Tonight even! ...Whoops, and here they come. 
Queen Beryl, giant smoke-Metalia, Endy's generals, a human army, some devils and a biiiig
swarm of black-shadow'y, snake'y creatures came flying to the moon. (- Srsly, how
did they get there?! -Magic! Probably just magic again. It explains any
plot-holes so nicely. >_<) 
There was a big fight. The castle was nothing but dust pretty soon. And everyone died. And I mean *everyone*. Some sources say, Venus was especially dedicated and even had some awesome sword (the "Sword of the Mystical Silver Crystal" or - much shorter - the "Holy Blade") that she stabbed Beryl with, giving her last breath... -after Princess Serenity used the same sword to commit suicide.
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| Inner Senshi combining their attacks against Metalia in the anime - without success. |
Other sources say, Queen Serenity did defeat Beryl and Metalia using her magical Silver Crystal.
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| Pink glow = Crystal Power |
Endy died defending his Princess, but she was also killed / killed herself.
The only ones left in the end were Queen Serenity and the two Mau, Luna
and Artemis (which are basically talking alien-cats, but we don't know
for sure what their job on the Moon was 'cept for not getting killed in Beryl's
attack). They had a little talk during the Queen's last breaths.  |
| Q-Sere deciding to die for her child's future |
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| Fly little bird~ |
And the Queen explained, that she would do one last thing:
Use her Crystal to send all the fallen ones to earth, for them to be reborn and live happier, carefree lives.
(After being weakened by using the stone to fight Beryl & Metalia, this was a lethal plan...)
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| "See you in another life~" |
(Luna and Artemis were put into some kind of stasis-tubes and sent after them.)
Two things, that I might add here:
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| (Is that Neptune in that other bubble?) |
2.) There's word, that the Sailor Senshi came from other planets. The heirs of their names-giving planets main royalties, making them all princesses too. Implicating there had been humanoid life as well on each solar system's planet - which was never mentioned again, but obviously isn't there anymore.
Were these people somehow killed during this war as well? If so, have they also been included in the wish? Have they all been reborn around the same time? Are they all in Japan!?
One could say, that's the end of the tale of the Silver Millennium, but there is a little sequel:
Because, there were actually more than four Solar Senshi active at that time. (Actually, the following had even been around much longer!) Pluto for example. She was... surprised by the attack as well (?) and went "really quick" to gather Uranus and Neptune from somewhere and "hurry" to Saturn, use three mythical items called "The Talismans" that each of the three possessed, to unlock Sailor Saturn's stasis chamber and release her.
Saturn was even back then known to be the ultimate weapon, so this was a very smart move of Pluto.
Too bad, that by the time they all arrived on the Moon, there was nothing left to save....
Geez, Pu. Timing wasn't exactly your thing back then, was it?!
Well, this was possibly one other reason for Pluto to go to the Gates Of Time And Space - training her sense of time a bit, hah! ..Another might be, because Q-Serenity was *still* alive and told her so.
Saturn, either bored or frustrated because the first time in ages that she got to run around in her fancy boots, she ended up standing in puddles of blood, or because she thought cleaning up by hand would take forever, swung her Silence Glaive. As a result, Uranus, Neptune and herself died (because Saturn using her ultimate power is by default lethal and releasing such energy basically tears her body apart, atom by atom) and, if she was *still* alive at that time, also did Q-Sere.
We can only assume, that those three senshi also had been included in Q-Serenity's awefully vague wish to be reborn with the others.
And that's the end of Silver Millennium. All dead. The Moon was (mostly) swiped clean by Saturn's attack. And Pluto sat at her Time Gate, waiting for the Princess and her guards to be reborn, probably picking up the habit of knitting really long scarves.
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That's it.
I hope, you enjoyed~
And yes, I left some PGSM-details out (it's been a while since I watched that, but I recall it to be pretty close to the manga-version). This is to be considered rather an overview of the events that took place and why. Yet, it's mostly for entertainment ^_-
PS: I used the names based on their japanese meanings and romanisation, as wikimoon does.
Also, I used google to find the manga scans. The actual origins, in particular for the translated one, got lost on the way... I hope, nobody feels offended by me using them like this. (If you find your own manga scans here, please let me know and I'll give proper credit / link back / remove them!)
