jan 1, 1066 - Norman Conquest
Description:
Signifies the transition from Old English to Middle English in which William the Conqueror invaded the Island of Britain and settled there with his nobles and court. The newly settled Normans spoke a rural dialect of French which has considerable Germanic influences. This dialect of French later became known as Anglo-French. This "dialect" soon became the formal language and since it's introduction the usage of the previous language spoken by Anglo-Saxon's (Old English) decreased significantly.
Added to timeline:
Middle English
Date: