original: In medieval England, the territories of Lancashire and Cornwall were made duchies, with certain powers accruing to their dukes.
simplifications: In medieval England, the territories of Lancashire and Cornwall were made duchies.  Certain powers given to their dukes. In old England, Lancashire and Cornwall were duchies, where dukes had some powers. Lancashire and Cornwall were made duchies in medieval England. Power of their dukes increased over time. In medieval England, the territories of Lancashire and Cornwall were made duchies. Certain powers were given to their dukes. In medieval England, the territories of Lancashire and Cornwall were made duchies. Certain powers went to their dukes. In medieval England, Lancashire and Cornwall were made duchies governed by dukes. In medieval England, Lancashire and Cornwall were made duchies, with certain powers accruing to their dukes. In Middle-Age England, the areas of Lancashire and Cornwall were under control of duchess's and dukes. In medieval England, the territories of Lancashire and Cornwall have been made duchess, with certain powers coming from their dukes. In old England, the cities of Lancashire and Cornwall were made into duchies, a place ruled by dukes.