Simplify the following text for a Grade 10 native English-speaking person.
Original: In 1691 Halley sought the post of Savilian Professor of Astronomy at Oxford , but , due to his well-known atheism , was opposed by the Archbishop of Canterbury , John Tillotson and Bishop Stillingfleet .
Simplified: In 1691 Halley sought the post of Savilian Professor of Astronomy at Oxford University . As he was well-known as an atheist , he was opposed by the Archbishop of Canterbury , John Tillotson .