French was the official language of England for about 300 years

After William the Conqueror took over England with the Normans and crowned himself king, the French language actually became the official language of England for nearly 300 years, from 1066 until 1362. The nobles, the court, and the government at that time spoke almost solely French, while many peasants continued to speak common English. These 300 years had a lasting impact on the English language - it is thought that nearly half of the words in the English language have roots from Norman French, which would have mixed into commoners English during that time.