"Even without records, we have more than enough reason to believe that the Citadel began as a court of scholars and priests. Assembled by a second son of House Hightower. When he died, his elder brother raised the Citadel so that wise men would always have a home in Westeros and could continue the enquiries and debates that had given such joy to his younger brother."
Pycelle[[Oldtown (Histories & Lore)
King Urrigon Hightower was a King of the Hightower and the founder of the Citadel.



When Urrigon's brother Peremore died, Urrigon supposedly granted the area that would become the Citadel to serve as a home to the scholars and priests that Peremore had surrounded himself with. It is believed that the learned men were precursors of the Order of Maesters.[1]

See also