On Thaurissia and Amoreen

This book, given to you by Ashfallen is a very interesting tome. The pages within do not match each other in size or handwriting, and the whole book has been bound together with magic and some careful gluing so the smaller and flimsier pages will not be easily ruined.
The roughly 200 pages in the book are all on different grades of paper, and in different handwriting. Many are in code, with notes indicating that the bookbinder suspected that they were related to the topic, but was unable or unwilling to provide a decryption key. Other pages have copious amounts of notes, as various authors have begun to try and pick apart various entries and combine them with information gleaned from other sections.
The handwriting and languages contained within span the last 10,000 years, going back deep into the 4th age. Common begins to evolve to the language we speak today, and while languages like celestial and elven are comparatively static, the number of words in the languages are staggering. Every few millennia some words fall out of favour, and others gain new meanings, making old celestial especially difficult to parse. As a written language Thaurissian is a nightmare, and it's clear that it's an elaborate pidgin language, mixing elements of archiac dwarvern, undercommon, and at least two other languages that are long dead.
Leafing through the many pages, it is clear that most of the documents contained within are only tangentially related to the topic at hand, but slowly some of the history has been put together. At the end of the book is a short, neatly written section collating all the knowledge gleaned from the previous pages. It is written in painfully neat infernal, although the word choice strongly hints towards Aklo being the speaker's primary tongue.
"The history of the nations of Amoreen and Thaurissia are particularly well obscured. This does not seem malicious, but rather the result of an unfortunate events, coinciding in an unfortunate manner. Some time just before 900D, the great warrior Alishmal blinded the gods, such that they could not see much of our planet. Alishmal's motives are well known, but do not strictly relate to what came next.
As Alishmal and their temple sank beneath the waves of the Violent Sea, the waters were becalmed permanently, and the change in climate (both in the hydrosphere and the arcanosphere) caused devastating changes to the local area. While the loss of divine magic and much of the ambient moisture was devastating to the humanoid species, the newly revealed metal veins and fluxing arcane magic brought the dragon flights forth.
The ruined lands were once inhabited by the proud Amoreen people, who worshipped Amotra, goddess of peity and kindness. While there was once a thriving polytheistic culture, only Amotra was strong enough to maintain contact with the material plane for very long, and so gradually all worship fell to her. Amotra's siblings, Assyr and Amoyr lent Amotra their strength, protecting the material plane just a bit longer.
From the caves and mountains to the north came the clans of the Fatherless, races of dwarves long since cut off from their god. The dwarves united their clan under one banner and named themselves "Thaur-Assyr", meaning "Step sons to Assyr", referencing how Assyr had stood up to protect them when their god, The Father, was unable to contact them until Assyr too was unable to help them. The name quickly became "Thaurissia" as the various dialects merged together, while the Amoreen people's name gradually became "Amon" (the long "ree" sound was unused in the Thaurissian language).
The nation of Amon'Thaur thus founded, the Thaurissians (now encompassing all members of Amon'Thaur) stood against the dragons, their customs and languages blending into the more typical "Thaurissia" that history occasionally remembers. The Thaurissians held their own for many decades, until the damage from Alishmal's work had passed, and the Thaurissians witnessed the birth of the first new god when Amoyr chose a mortal to ascend. A divine path thus re-established, the Thaurissians would go on to defeat the dragons, and restore their homeland to the verdant plain it once was.
The dwarves used their divine might to craft wonders, and augment themselves with clerical might. The Amoreenians used the magic to bring back the dead, using fallen generals to lead their army to greatness.
All was not well, however. New gods had arrived, and the monothesic Thaurissia quickly decayed to its component parts. The dwarves went back to the worship of the Father, and returned to their liberated mountainhomes. The Amoreen people (mixed with the quickly growing human population) were split; the power base of what was once Amoreen was now unimaginably wealthy, compared to how they were before the war with the dragons had begun. It was no longer fitting, they said, to continue to worship Amotra and her vows poverty. Instead, they turned their focus to Abadar, a god more fitting to their new station.
The remainder (mostly the other humanoid races, such as humans, gnomes, halflings and the like) wanted to return to their worship of Amotra. In the end it was decided that the land should be split. The treaty of Amoreen was signed, and the nation was effectively ended. Those who would go on to support a monothesic culture around Abadar took the best land, and named it Aberdeen in honor of their new god. The remaining people were left to found their own cities (or rebuild in the ruins of the old), and although attempts were made, these independent nations would unite under the one banner."
-The Dreamer of Burning and Light