|Book||Fire and Blood (mentioned)|
Goodwyn was an archmaester of the Citadel during the early reign of King Jaehaerys I Targaryen.
Fearing that Septon Mattheus might become the next High Septon after the death of the High Septon in 54 AC, King Jaehaerys I Targaryen and his sister-wife, Queen Alysanne Targaryen flew to Oldtown to oversee the election of the new High Septon.
When the royal couple arrived at Oldtown, the High Septon had already been interred in the crypts beneath the Starry Sept. Jaehaerys gave a eulogy nonetheless, addressing a huge crowd of septons, maesters, and smallfolk in the plaza. At the end of his remarks, he announced that he and the queen would remain in Oldtown until the new High Septon had been chosen. Afterward, Goodwyn would wrote about the reaction of the crowd: "The smallfolk cheered, the maesters nodded sagely, and the septons looked at one another and thought on dragons." 
- ↑ 1.0 1.1 1.2 Fire & Blood, Birth, Death, and Betrayal Under King Jaehaerys I.