
The Citadel stripped me of it.
Game of Thrones Season 3, Episode 5

You don't get thrown out of the Citadel
without good reason.
Game of Thrones Season 6, Episode 3

The Citadel?
Game of Thrones Season 5, Episode 5

I hear you studied poisons at the Citadel.
Game of Thrones Season 4, Episode 3

You are a maester of the Citadel,
Game of Thrones Season 2, Episode 6