Simplify the following text for a Grade 15 native English-speaking person.
Original: Founded in 1829 by Lieutenant Governor of Upper Canada Sir John Colborne , UCC is the oldest independent school in the province of Ontario , the third oldest in the country , and is described as one of Canada 's most prestigious preparatory schools , having many of Canada 's most powerful and wealthy as graduates .
Simplified: Founded in 1829 , UCC is the oldest independent school in the province of Ontario , the third oldest in the country , and is described as the most prestigious preparatory school in Canada , having many of Canada 's most powerful and wealthy as graduates .