It is the oldest established nation in Aporea. During the early years of the Age of Parting, high elves settled there and built a kingdom that they believed reflected that of their god. Since then the nation has been taken from a high elvish rule by the much larger population of humans. Most high elves now live in Inhonoris, the first city of Yraldrig, and have their own government.
Established in the early years of the Age of Parting, Yraldrig is the oldest known nation in Arbressian. It hasn't changed its borders much in all that time despite going through wars and land disputes. They did try to acquire No Man's Land in a war that spanned years and ultimately led to the people of No Man's Land establishing a new country named Eischland with its own royal family and government.
The most notable change that did occur was after the civil war of Yraldrig in the Age of Awakening. Humans who felt looked down upon by the high elf royalty began a revolution to unseat the elves and put themselves in power. Something that succeeded fairly quickly as the high elves suffered great losses and with already being outnumbered vastly by humans they worked out an accord. They would keep the city Inhonoris and the humans got full reign over the rest of Yraldrig.
There is no recognised religion in Yraldrig. The humans demolished all temples outside of Inhonoris when they took over the rule and they do not believe in or worship any gods.
Other races in the country are allowed to pray to whomever they wish but organised religion is against the law.
Yraldrig has a very contemptuous relationship with Eischland with their polar opposite views on so many things. A tenuous peace is kept thanks to Inhonoris being located so close to the border between the two countries which holds Yraldrig back from going into a full scale open war.