This question needs to be moved to the Social Sciences Discussion Forum so you can benefit from lots of input and ideas from others. There are many ways in which events that took place during the Middle Ages in England impact us today.
One example would be to consider all the changes that came about because William of Normandy overcame his illegitimate birth and various conflicts with King Henry 1 of France to become leader of the French Norman forces that invaded England in 1066. William's forces defeated the English and William "the Conqueror" was crowned King of England on Christmas Day, 1066. During his rule, much governmental authority and power was centralized and given to the monarch, Norman architecture became a major influence in England, and - probably the major influence on our lives today - the spoken and written language in England was greatly changed by the introduction of the French language into the culture of England. The huge variety of words in today's English language that come from Latin roots can ultimately be traced back to William the Conqueror's impact on England.