Sylvia edits

Sylvia--

[His father] had discovered it on the rocky beach of one of the far islands and immediately proclaimed it the perfect gift for his queen. It took over a dozen men to bring back to the Sithein and when she saw it, she declared that it was the perfect chair, declining even the thinnest pillow. A thick double layer of wool was wrapped around her waist and then pulled around the back and over her shoulder to tuck in at her waist. She claimed it was to ward off the cold damp of the Sithein but Tyrae suspected it was to cushion herself from the hard stone of her "perfect" seat.

Watch all the "its". What is "it"-- a stone? A chair? A stone chair? Something else? A very large conch shell (well, why not? It was found on a beach :)?
[His father] had discovered (NOUN) on the rocky beach of one of the far islands and immediately proclaimed it the perfect gift for his queen.

Do you need "immediately?" "Proclaimed" is a big strong verb. You already have three modifiers in the sentence. Remember that you don't need to make every sentence bristle. :)

It took over a dozen men to bring back to the Sithein and when she saw it, she declared that it was the perfect chair, declining even the thinnest pillow.

Now if you use a noun in the first sentence, you can use it instead of one of the "its" here. The first "it" is that non-descriptive universal it, but the rest presumably refer to the chair (or whatever). Let's just see if we can get rid of that first "it"-- sometimes that's more trouble, but we'll see:

A dozen men were needed to bring the stone back to the Sithein and when she saw it, she declared that THIS (gets rid of another it) was the perfect chair, declining even the thinnest pillow.

"she?" His mother? The queen? Repetition of important nouns is not a terrible thing. Too many "its" is worse. :)

was the perfect chair, declining even the thinnest pillow.

Oh, those participles. Now what does "declining" modify? Chair? It (or this)? Oh! She!!! That's kind of a few nouns back. Try putting the modifier close to the noun it modifies or rewrite:
and when she saw it, she declined even the thinnest pillow, declaring that THIS (gets rid of another it) was the perfect chair.

That also ends the sentence on the more important word-- the chair, not the non-existent pillow.

A thick double layer of wool was wrapped around her waist and then pulled around the back and over her shoulder to tuck in at her waist.

Is there a reason you went passive here? There are reasons for using the passive voice, mostly to hide the actual subject ("This bill must have been lost, as it was not paid"). But your default should always be active voice-- use passive only when you decide it's better in this context. (There are reasons to use passive, and one is simply that in some sentences, it allows for a structure that you want for some reason... but I don't think that's true here-- maybe it is?)
Here's how that sentence would be in active voice:
She had to wrap a thick double layer of wool around her waist and pull it around the back and over her shoulder to tuck in at her waist.
Is that better? Or does it lose something going active?

She claimed it was to ward off the cold damp of the Sithein but Tyrae suspected it was to cushion herself from the hard stone of her "perfect" seat.

Another "it", and this presumably refers to the wrapping up, not the chair? Try "this" instead.

Also, you have two complete independent clauses there, so there should be a comma before the conjunction (but).

I don't know about the quote marks around "perfect". Why not let the irony be there without too much fingerpointing? Like:
She claimed this was to ward off the cold damp of the Sithein, but Tyrae suspected it was to cushion herself from the hard stone of her perfect seat.

So-- watch the pronouns there-- "it" can refer to almost anything. So:
She claimed this was to ward off the cold damp of the Sithein, but Tyrae suspected she wanted to cushion herself from the hard stone of her perfect seat.

What do you think?
Alicia