I imagine the moon might be a metaphor for the Golden City.
Yeah I know I'm pulling this one from nowhere
, but we had the Sun which seems to be a natural part of the world , something powerful.
In the Dalish tale (and let's face it , part of it is probably very wrong but that's all we have for the birth of the elven people/civilization), the only thing created is the moon by Mythal.
You can say the Golden City is a pale imitation of the Sun , yes it's shiny ... in the fade it's always there ,just like the Sun was supposed to be always there before Elgar'nan threw him into the abyss.
I said this earlier but there is a raw fade , all dark rock , lyrium veins (I imagine Titans/earth ) and it's always night and there is just a ribbon of light left , and the Golden CIty now Black also always there.
It could be something that did happen because in ..I can't remember in which DA book I read that , but anyway it is written in theory you could find in the Fade , the origins of the world .
And that dark vision in the raw Fade , or memory ..well it sounds like what happened with Elgar'nan and Mythal , in the tales all went dark."With the sun gone, the world was covered in shadow, and all that remained in the sky were the reminders of Elgar'nan's battle with his father—drops of the sun's lifeblood, which twinkled and shimmered in the darkness"
So did the Elves created the Golden City as a pale imitation , if the city was golden in the raw fade perhaps things would look better?
/Head desk.
There is potential credence for this theory, I also have thought about it.
The reason she created the "moon" however might not have been as "PG" as is depicted in the Dalish legends. It could have been made to hold back the blight, perhaps an unintended side-effect from with the absence of the "sun" which gave it room to develop (or re-purposed for this reason, having been a temple dedicated to the "event" first. By event I mean Elgar'nan "beating" the "sun" into submission).
"drops of the sun's lifeblood, which twinkled and shimmered in the darkness". This quote seems to indicate the stars, but life blood is an interesting definition to describe them. Much like blood magic and now lyrium being Titan's blood. It all seems to be connected in terms of a magic booster. Using the "sun's" lifeblood to create the "Golden City" makes sense. The "blood" could've helped boost Mythal's powers which would explain her capacity to create such a structure in The Fade, the same way lyrium boosts magical abilities (as we know it takes 1000's of "servants" to maintain and create a "pocket-dimension" as well as the temple lying within pre-veil i.e. as described in the "Raising the Sonallium" Codex).
Again, the question is whether she would've built it specifically to honor the sun (i.e. functioning as a temple) and then used it in desperation as a prison (to hold in the "blight/taint") or if its intended purpose was always as a prison built because of the consequences of defeating the "sun".
Edit: also the quote "drops of the sun's lifeblood, which twinkled and shimmered in the darkness"
reminds me of this codex
"She took the radiance of the stars, divided them into grains of light, then stored them in a shaft of gold."
"Andruil, Blood and Force, save us from the time this weapon is thrown."
interesting parallels in my opinion
The spear with a shaft of gold is also described at the end of the codex as
"glowing with unbearable heat"
shaft of gold, a golden city, extreme power from, blood, light and heat. They all are recurring themes, same as darkness and the blight.
"The slaves have disappeared" (blood sacrifice). "Light radiates from the eidolon's narrowed eyes."
"...Immensely graceful vine that flowers with the heat of a copper sunset"
I could add more but I think I've made my point. Anyways we just have to keep an eye out for more of these similarities found in all the different codices and sources we happen upon, which will help us puzzle together a more concrete image of what was actually going on pre-veil.