The real question is: Given a text by William the Conqueror and Theodosius, how many words could a French or English speaker identify based on similarities with words he/she commonly uses?
That probably isn't the question you wanted to ask. But in case it is, you can see a book compiled by order of William the Conqueror here: https://opendomesday.org/book/bedfordshire/01/
High-resolution image of the same page: https://opendomesday.org/media/images/bdf/01.png