Regarding spelling changes, please see my posting on your other thread, the answer is Yes. Parish records were introduced in 1538 by Thomas Cromwell chancellor of Henry VIII. Few registers date from this date, more from 1558. Prior to 1538 you are into Medieval records, though it is possible to get further back, and it has been done, it is more difficult, the sort of thing you will be looking for is a manorial record, if your ancestors held a tenancy, a farm for instance. It is a subject on its own account and I suggest you do some googling to get an idea what is available. Good luck.