The battlefield equipment and tactics at the time of the Norman Invasion of England.

The Normans were something new to all the native peoples of Britain in the second half of the 11th century, and their style of warfare was different in many respects. The elite of the Norman armies were the knights fighting from horseback. The open plains of northern France were ideal for horses, and the use of cavalry had a long tradition in France. The Franks themselves were expert cavalrymen, and the Viking settlers of Normandy …

…its language. The Norman French spoken by the invaders became the language of England's ruling class. The lower classes, while remaining English-speaking, were influenced nevertheless by the new vocabulary. French became the language of the affairs of government, court, the church, the army, and education where the newly adopted French words often substituted their former English counterparts. The linguistic influence of Norman French continued for as long as the Kings ruled both Normandy and England.