Wilde would attend the school in Ireland until 1871 (age nine to around age sixteen or seventeen) and was awarded for being one of its top students of classics consecutively in his final two years of attendance. When he signed the Roll Book for the school, he neglected the "Wills" part of his name and spelled "O'Flaherite" incorrectly, perhaps because the name came from a line of notorious Galwegian kings. He would be given the name "Grey Cow" in his time there, as he had given nearly every boy at school there a nickname, through his own he didn't enjoy. Richard Ellmann writes that the name was "perhaps premonitory of Doria[n] [Grey's] surname." Other notable alumni of the institution include novelist Samuel Beckett and Anglican clergyman Henry Francis Lyte.

Sources: https://www.biography.com/writer/oscar-wilde

https://worldhistoryproject.org/1864/oscar-wilde-attends-the-portora-roy...

Oscar Wilde by Richard Ellmann.