Complex sentence: The church which was built in three stages which started in 1456 when the South Chapel was built this was followed by the building of both the North Chapel and the Tower built in 1648 and 1741 respectively.
Split into simpler sentences: The church which was built in three stages which started in 1456 when the South Chapel was built. This was followed by the building of both the North Chapel and the Tower in 1648 and 1741 respectively.