- This article is about the character during the War of Conquest. For the title see High Septon (title).
- "When Aegon the Conqueror landed in Westeros, the High Septon locked himself in a sept for seven days and seven nights. Finally, the Crone lifted her golden lamp, and showed him the path ahead. The High Septon himself would anoint and crown Aegon as Lord of the Seven Kingdoms; and the Faith Militant rallied behind Aegon in governing his newly united land."
- ―High Sparrow
The High Septon held the position when Aegon I Targaryen and his sisters Rhaenys and Visenya launched their conquest of Westeros. He locked himself in the Starry Sept for seven days and nights, during which he prayed to the Seven for guidance. Eventually, the Crone lifted her golden lamp and showed him the way forward. He then anointed and crowned Aegon as the Lord of the Seven Kingdoms. He conceded Aegon's marriages to his sisters as a relic of his Valyrian heritage, which he hoped would soon fade.
In the books
In the A Song of Ice and Fire novels, the High Septon locked himself in the Starry Sept and spent seven days and nights praying and fasting, taking only bread and water as nourishment. Upon emerging, he announced that the Faith of the Seven would not oppose House Targaryen, as the Crone had shown him that doing so would lead to the destruction of Oldtown by Aegon's dragons. Lord Manfred Hightower, a pious man and the Lord of the Hightower, heeded the High Septon's prophecy and kept his forces at Oldtown. He opened the gates of the city and submitted to Aegon's authority, after which the High Septon crowned and anointed Aegon, putting an end to any opposition the Westerosi people had towards Aegon.
Centuries later, the High Sparrow recounts the story to Cersei Lannister during a meeting at the Great Sept of Baelor, stating that he must fast and pray as the High Septon did. She asks if it will be for seven days and nights, and he replies that it will be for as long as it needs to be.