Wordbuild Compendium

The humanized world of Equestria I have created for my story, One is Silver, is rather extensive (and one of its strongest points). To go into depth within the story itself would drag it out and distract from the actual read (it has so far been called "like reading an encyclopedia.") I will try to explain all the most necessary parts within the story (the significance of the races, all that good stuff) but there won't be room for all the side details, so I'll be working on this Compendium to accompany and supplement the story. Much of it will sound familiar from the story, but completion is what's stressed here.
[This Compendium will take some time to complete. Hold your horses. I will also make a separate post later for full figurative and literary explanation, for those interested in or confused by the underlying elements to the story.]
[Edit: Come to think of it, maybe I should just put it in the author's notes of the chapter in question.]
[Also, I'd like to say that this history and build is open to any and all who'd like to use or adjust it.]

Timeline

First Age: The Age of Alicorns

First of all, the Alicorns (resembling humans) are not to be confused with the "True Alicorns," which are also known as the "perfected beast" and never came into being. The Alicorns are often represented as their four-legged counterparts in later art, however.

It's not clear which came first, the Alicorns or the universe itself, as there was nothing before them that could observe any existence. Similarly, the universe could just as easily be born of the Alicorns as they could of it. All that is clear is that they are the first beings, along with Discord and the other Spirits of Bane. They share a link with the universe known as the "Augur," comparable to "the Force" in Star Wars.

The world at this time is flimsily structured, a surreal, Eden-like state. It is the Alicorns that sculpt the world, but can only do so in massive collaborations. Plants were the first to be added, and to help them, the sun, moon, and stars were formed. But they really just hung there in the sky, static. Celestia then designed the first creature, the horse, from then on seen as sacred. Luna, being the jealous type, tried to one-up her sister with the Pegasus and the Unicorn. She even made them immortal. These inspired more and more creatures, each successive derivatives of the horse. Every Alicorn designed some being, except for one, whom I call "Astrid." (working name, doesn't actually appear in the story)

At some point they noticed that the sun and moon were doing more harm than good as they were, and must be regulated. Celestia and Luna received the honor for their prized contributions. They control them trough these necklaces, Celestia's is a pearl set in gold (which the military later labels "the index," simply meaning an object of significance) and Luna's is a ocean-to-night-blue one set in a silver chain.* This happened the same day Discord presented his love, Celestia, with mankind as a gift. Man was seen by the Alicorns as an abominable taint on their perfect world, and Discord was scorned for it.

This day, the first true "day," marks the end of the First Age.

*Note: I don't really have anywhere else to say this, so it might as well be here: this is figurative and relates to the title. "One is Silver" comes from "Make new friends, but keep the old; one is silver, one is gold." Gold and silver are used pervasively throughout the story to represent old friends/the familiar and the foreign/un-trusted, respectively. Note even the hair of Celestia and Luna. They are both themselves symbols.

Second Age: The Age of Blight

The time referred to as "when Discord ruled Equestria." (except that here, it hasn't been founded yet)

History is written by the victor, and the detail that it was Discord that made Man, not Celestia, has been lost to the years. This notion started merely out of assumption. It never really occurred to anyone that anyone other than Celestia would have created them.

Man sprung up in tribes, each idolizing an animal or mystical beast. These include the Bysen, Mullen, Zebren, and a host of other, smaller tribes scattered around in what remains the Outlands, which is anywhere not considered "civilized."

Discord releases his Blight upon the world, killing all immortal beings. The phoenix is the exception: it can technically die. The Unicorns and the Pegusai give their magic and flight to the humans so that their legacy may yet live on. Thus, the Starcrest and the Seraphim are born. The jewels protect Celestia and Luna, and they give Discord chase. This lasts for the entire duration of the Age. Near the end, Discord encounters Astrid, who survived the Blight by severing her link with the Augur in a dark fit of angst over her valueless life, rendering her mortal. Now she must feed on goodwill to sustain her, in addition to conventional bodily maintenance, which has lately been running in dangerously low supply. The Blight mutated her, and now she can take any humanoid form she likes. Additionally, Discord has her spread spores that will eventually grow to be the Changeling army under her (his) command. Seeing her as an asset, he preserves her in a chrysalis, saving her life, just before confronting Celestia and Luna, accepting his stone fate. He is sealed in Luna's gem, and has the full intention of swaying her to his side.

It is this final battle that concludes the Age, and the site of it becomes Gallopstride (my Canterlot), capitol of the Equestrian Kingdom, founded when the Starcrest, Seraphim, and Earthbound collectively submitted themselves to their guardian and queen.

Third Age: The Age of Civilization

Well, this has been pretty much a TLDR of the prologue so far, but now we're getting to some good stuff.

The three main races got along pretty well and were the first to unite primarily because of what could be called religious reasons. Each champions and holds sacred one of the three horses, and got along in concordance because of their shared views. Not all joined Equestria, of course. The Mullen to the south, worshiping the donkey, a close relative of the horse, get along well enough with Equestria, but were too stubborn to join with them. They remain their own independent entity in the Outlands.

The west side is, well, pretty much like the "wild" American west, myths about how "wild" it is and all.