Simplify the following text for a Grade 9 native English-speaking person.
Original: Under Bishop John Harewell , who raised money for the project , he built the south-west tower of the West Front and designed the north west , which was built to match in the early 15th century .
Simplified: Under Bishop John Harewell , he built the south-west tower of the West Front and designed the north west , which was built to match in the early 15th century .