Warning – Spoilers! This brief history of Roshar will include spoilers for The Way of Kings, and possibly all the current books in The Stormlight Archive. These spoilers will hopefully only relate to the lore and history of Roshar, rather than the plot of the books, but often with Brandon Sanderson’s work, these two things can intertwine.
We also have a spoiler-free Beginner’s Guide to The Stormlight Archive if you definitely want no spoilers at all before reading this series.
Twelve to thirteen thousand years prior to the True Desolation, so before the Shattering, Roshar was created by Adonalsium (the being from whom all Investiture is obtained). At this time, people lived on the planet and the spren and highstorms existed too. The main inhabitants of Roshar were the singers.
Humans fled from a neighbouring planet, Ashyn, in the Rosharan system, bringing Odium with them. This eventually led to the First desolation, a major conflict between the humans and the singers.
This is where there could be spoilers for some of the books in The Stormlight Archive, so I will skip over some of the timeline and just say they there were complications after the end of some of these conflicts which eventually led to the formation of the Knights Radiant.
The beginning of The Way of Kings and much of the mystery of that book stems from the end of the Last Desolation, which resulted in the death of one Herald, and nine survivors. The survivors proclaimed that this was the end of the war against the Voidbringers, but things were not that simple.
I cannot go into any detail, but many years later, Roshar saw The False Desolation, which stems from the end of the Last Desolation. The Knights Radiant end up doing something they are so ashamed of, in addition to learning the truth about the origins of humans on Roshar, they abandon their oaths on the Day of Recreance.
Recent History Prior to The Way of Kings
After the Day of Recreance, humans pick up the fallen Shardblades and Plates of the Knights Radiant and consolidate power, fighting amongst themselves until a delicate balance is created.
A text called Arts and Majesty was written and used to keep women from wielding these weapons.
There were many conflicts, with men and churches attempting to conquer and rule over the whole world, but the most notable one is the War of Loss. This war was won by Sadees, the Sunmaker, who drove out the Vorin Church Hierocracy, united Alethkar, and attempted to conquer the rest of Roshar.
These events continued to shape the world and societies of modern Roshar, with ardents from the Vorin Church becoming slaves for the rulers of Alethkar.
The Way of Kings is set after the Reunification of Alethkar in 1158. Gavilar Kholin reunified the ten princedoms, much like Sadees did in the past, and ruled as King.
So, there is a brief history of Roshar from The Stormlight Archive. I hope there were not any spoilers in there and it helps you understand Brandon Sanderson’s fiction world a little better when you read The Way of Kings and the rest of the series.