The battle in 1066 that led to the Norman conquest of England was the Battle of Hastings. Fought on October 14, this significant conflict saw William the Conqueror, the Duke of Normandy, defeat King Harold II of England. The battle was pivotal in altering the course of English history, resulting in Norman rule and extensive changes to the English social structure, culture, and language. William's victory established him as king and brought feudalism to England, leading to a blend of Norman and Anglo-Saxon traditions.