How long did England own northern France?

Answer 1

I think you will find that it was the other way around.
After the Norman French defeated the English in 1066 the victors took over all the best land and most of the major aristocratic families in England are descended from these people.
From that date England was ruled by monarchs who were French who had large land holdings in France and fought many wars there against other French nobles until Henry Tudor the Welshman become king in the fifteenth century.
For most of that time England was considered to be a province of France

Answer 2

Never...Since William the Conqueror (1066) the duke of Normandy, a part of northern France, were also kings of England. Their followers, the Plantagenets, counts of Anjou, were kings of England and Dukes of Aquitaine, which is a southern part of the Kingdom of France, near Spain. They were quite french, spoke only french, and treated the true English, the Saxons, like slaves. There were no such things like England or France during the XIIIth century. The war was a mere struggle between aristocrats for obscure inheritances.

Answer 3

The Normans Invaded England in late summer of 1066, Calais fell to the French in January of 1558 so it would be 491 years. However the Channel Islands are part of the Duchy of Normandy, and are still controlled by the British.