AES SEDAI

In the Age of Legends: the Age of Legends is a relatively utopian society. Men and women with the ability to channel used the One Power to aid all of mankind—as scientists, healers, philosophers, etc.—constantly developing new innovations and technology to make everyone's life easier. In the series these people were therefore known as Aes Sedai, meaning "Servants of All" in the Old Tongue. In spite of the use of the word “servant,” Aes Sedai had considerable status and respect, gained from their use of the One Power. The characters called Aes Sedai convened in the Hall of the Servants in the city of Paaran Disen. The greatest Aes Sedai of the Age of Legends was a man named Lews Therin Telamon, also known as The Dragon.

In the Wheel of Time story, The One Power is divided into male and female halves, known respectively as saidin and saidar. Men who can channel do so using the male half and women use the female half. The greatest works of the Aes Sedai were always performed by groups of men and women channeling together.
It is explained at various points throughout the story, certain Aes Sedai felt that the separation of the two halves of the Power constrained them. Researchers working at the Collam Daan discovered what they thought was a new source of power able to be channelled by both genders. Mierin Sedai (later Lanfear) and Beidomon Sedai bored into it, soon discovering that they had unwittingly enabled the Dark One, formerly imprisoned outside of Time, to influence the world. The power they sensed was in fact the True Power, a dark force akin to the One Power that stems from the Dark One. The former utopia began to slowly decline, until the outbreak of the War of Power, in which many Aes Sedai went over to the Shadow and commanded the armies of the Dark One. The most powerful "dark" Aes Sedai were selected by the Dark One and called themselves the Chosen, although the rest of the world named them the Forsaken. By the end of the War of Power, thirteen of the Forsaken remained, although there had been others who died before the resealing of the Dark One.
Later revealed by Jordan, in a desperate move to end the devastating conflict, Lews Therin Telamon and the Hundred Companions, all males and actually numbering 113, led a last-ditch assault on Shayol Ghul, successfully resealing the Bore and trapping the Dark One, as well as (almost) all the Forsaken, outside of the world. However, the Dark One's final counterattack tainted saidin itself, and the surviving Hundred Companions (sixty-eight in total) went mad instantly -- Lews Therin himself murdered his entire family, earning the title "Kinslayer". Over time all surviving male Aes Sedai were driven mad by the Dark One's attack on saidin. In their madness, they began to channel wildly, causing almost total destruction to everything that hadn't already been wiped out by the war, their powers even altering the geography of the world. Some few male Aes Sedai sought shelter in stedding, areas of the world in which channeling was impossible and the taint had no effect, but eventually all male Aes Sedai abandoned the stedding and went mad. By the time the last male Aes Sedai had died, the world map was all but unrecognisable, and the remains of humanity were scattered and destitute. This catastrophic period was called the Breaking of the World.
Among Aes Sedai in the time period of the series, some Aes Sedai, primarily the Red Ajah, believe that male Aes Sedai sheltering in stedding exacerbated the Breaking, making it longer and more damaging than it might have otherwise been. Others, primarily the Blue Ajah, hold that the Breaking might have destroyed the world entirely had all male Aes Sedai gone insane at the same time.
However, female Aes Sedai of the time Foresaw the Rebirth of the Dragon, and undertook several wonders (the Eye of the World, the Stone of Tear, Callandor, etc.) to guide his path and provide him with what he needed.