The Norman Conquest of 1066 had a significant impact on the English language. William, the Duke of Normandy, invaded England and defeated King Harold. As a result of the conquest, Norman French became the dominant language among the new Norman nobility and upper classes in England for the next 200+ years. English remained the primary language of the lower classes. Over time, the languages blended together as the Norman and English populations intermingled through marriage and social interaction. By the late 12th century, both the upper and educated classes had gained knowledge of English, while merchants and some middle class individuals knew French.