According to some scholars, Andraste was born at -203 Ancient (992 TE) in Denerim, which was then a fishing village. Her mother was an Alamarri woman named Brona and her father was the chieftain of one of the largest Alamarri tribes in what is now northern Ferelden, Andraste was a woman who rose to greatness first as a slave of the Tevinter Imperium, then as a prophet, war leader, and religious icon.
According to the legend, before the Maker spoke to Andraste, she despaired at the fate of her fellows. At that time, every night, her husband, Maferath would come to console her and each time Andraste would tell him her despair while shedding a single tear which Maferath captured in a vial. In the thirtieth night the vial was full and when dawn came Andraste saw her first vision of the Maker. Even though this legend is popular and has passed on for ages, no part of it is in the Chant of Light.
From an early age, Andraste suffered troubling dreams of a god known as the Maker. Over time she began to interpret these dreams as the answer to questions that plagued her, and she came to understand that the Maker was the supreme being who had abandoned the world when his people took up the worship of the Old Gods, those beings worshipped in particular by the Tevinter Imperium. According to Chantry canon, after having fled the Imperium and marrying the warlord Maferath, Andraste appealed to the gods but her prayers went unanswered. She would sing, and one day the Maker, enchanted by her voice, invited her to join Him at His side. She instead encouraged Him to return to humanity and forgive them, compelling her fellow Alamarri and others to accept the one true god of Thedas.
To the world, Andraste was an escaped slave from the Tevinter Imperium who came to power after the First Blight had ended and Dumat was slain. She fought against the Imperium, which had been significantly weakened by the First Blight. As part of the Exalted Marches, she conquered most of the south while fighting to destroy the magisters, whom she blamed for the Blight. The people she led in her campaign were the barbarian ancestors of the Fereldans, the Alamarri. She also joined forces with the elven leader and former slave Shartan and his people as they shared a common enemy in the Imperium. To the Imperium, Andraste was an opportunist, a barbarian taking advantage of their weakness. She led her rebellion against the Tevinter Imperium in the first Exalted March under the Maker’s sanction. Andraste’s March was greatly successful due in part to several unfortunately concurrent natural disasters, including droughts, famines and flooding, which decimated the Imperium’s farmland and, consequently, troops—a form of divine punishment, which Disciple Cathaire, one of her war leaders, contends. According to the Chantry teachings, the reason the Imperium did not fall entirely to her army was because of Maferath, Andraste’s mortal husband. Feeling that the barbarians had overextended themselves, he made a deal with the magisters to keep the south in exchange for turning Andraste over to them. She was burned at the stake in Minrathous. Her death is known as the second sin, which caused the Maker to turn from humanity once again. Yet, because of her, the Imperium, for all intents and purposes, was greatly weakened, and the Chantry was formed, focused around her teachings.
Archon Hessarian, who ordered Andraste’s execution, was the first person converted to following the Chant of Light. According to the Chant, the Archon saw the error of his ways as soon as Andraste was burned. It was he that put the sword through her heart to put her out of her misery, which is why the sword is a symbol of mercy in Andrastian lore, and later repented her execution entirely (though Chantry dissenters claim Hessarian only converted because he could not stem the tide against Andraste’s followers, only emboldened by the death of their leader, and repented his actions as a means to stay in power).
He turned on his former ally Maferath and ushered the way for the Tevinter Imperium to eventually become an Andrastian nation, though the Chantry as an organization did not yet exist at this time. As for Maferath, when his betrayal became common knowledge, his people abandoned and eventually murdered him.
Andraste had several children but they are all believed to have died in the civil wars that tore the south apart after Maferath’s death, and the unification of the Ciriane tribes in modern-day Orlais. There have been many claimants in the centuries since, saying they were descendants of survivors, but the Chantry has disavowed each of them. To date there are no known legitimate heirs to Andraste’s blood.
The official belief of the Imperial Chantry is that Andraste wasn’t, in fact, the Maker’s Chosen, but rather just an extraordinarily powerful mage.