Some basic everyday words in English come from Old Norse:
sky leg take window call dirty church
The Norman Conquest The Normans came from Normandy, Northern France in 1066 . It was the last invasion in England but had an enormous influence in many aspects of British life: habits, language, society, literature, justice, etc.
French Influence French was the language of the top of society (government, church, justice…) and little by little its influence spread a bit to the rest of the population who always spoke English. This is the birth of Anglo-French .
French Influence The Normans brought more than 10,000 words into English, 75% still in use and no longer felt as foreign. By the 13th / 14th centuries only the top class uses French. By 15th century it disappears but always as a favourite foreign language. With French also came a lot of Latin vocabulary.