Union of Brittany and France: The Duchy of Brittany is absorbed into the Kingdom of France.

The union of the Duchy of Brittany with the Crown of France was the culmination of a political process begun at the end of the 15th century in the wake of the Mad War. It resulted in the Edict of Union of 13 August 1532 and the incorporation of the duchy into the Crown lands of France, a critical step in the formation of modern-day France.

The Duchy of Brittany was a medieval feudal state that existed between approximately 939 and 1547. Its territory covered the northwestern peninsula of France, bordered by the Bay of Biscay to the west, and the English Channel to the north. It was also less definitively bordered by the river Loire to the south, and Normandy, and other French provinces, to the east. The Duchy was established after the expulsion of Viking armies from the region around 939. The Duchy, in the 10th and 11th centuries, was politically unstable, with the dukes holding only limited power outside their own personal lands. The Duchy had mixed relationships with the neighbouring Duchy of Normandy, sometimes allying itself with Normandy, and at other times, such as the Breton–Norman War, entering into open conflict.

The Kingdom of France is the historiographical name or umbrella term given to various political entities of France in the medieval and early modern period. It was one of the most powerful states in Europe from the High Middle Ages to 1848 during its dissolution. It was also an early colonial power, with colonies in Asia and Africa, and the largest being New France in North America geographically centred on the Great Lakes.