"The Middle Ages" is a thousand year period that covers everything from 5th Century sub-Roman petty kingdoms, to Justian-ian Byzantium, to the 8th Century Carolingian Empire, 10th Century Ottonian Empire and Cerdicing England, to 13th Century Scotland to the 14th Century Hanseatic League to 15th Century Spain, and many more inbetween. Is there a more specific period and/or location you have in mind?