The Middle Ages saw major changes in England beginning in 1066 with the Norman conquest. William the Conqueror, Duke of Normandy, invaded England and defeated King Harold II at the Battle of Hastings, establishing Norman rule. William implemented a feudal system dividing lands among his nobles, bringing Norman-French culture and administrative reforms. Feudalism established a strict social hierarchy from king to serfs. The rise of chivalry and courtly love influenced knights' behavior. Major events like the Crusades, Black Death plague, and Thomas Becket's martyrdom impacted society. Geoffrey Chaucer's Canterbury Tales, written in the late 14th century, provides insight into life at the end of the Middle