Mad War in the context of Charles, Count of Angoulême

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.

As a territorial principality of the Kingdom of France, Brittany had enjoyed varying degrees of autonomy since Clovis I was given authority over the Gallo-Roman domain during the 5th century. It was first recorded as a "duchy" during the rule of Nominoe in 846, in likely recognition of Carolingian overlordship. Over the centuries, the fealty demonstrated by the Duchy of Brittany toward the French king depended significantly on the individuals holding the two titles, as well as the involvement of the English monarchy at that particular time. The reign of Francis II, Duke of Brittany, was at an especially crucial time, as the nobles struggled to maintain their autonomy against the increasing central authority desired by Louis XI. As a result of several wars, treaties, and papal decisions, Brittany was united with France through the eventual marriage of Louis XI's son Charles VIII to the heiress of Brittany, Anne in 1491. However, because of the different systems of inheritance between the two realms, the crown and the duchy were not held by the same hereditary claimant until the reign of Henry II, beginning 1547.

Charles VIII, called the Affable (French: l'Affable; 30 June 1470 – 7 April 1498), was King of France from 1483 to his death in 1498. He succeeded his father Louis XI at the age of 13. His elder sister Anne acted as regent jointly with her husband Peter II, Duke of Bourbon until 1491, when the young king turned 21 years of age. During Anne's regency, the great lords rebelled against royal centralisation efforts in a conflict known as the Mad War (1485–1488), which resulted in a victory for the royal government.

In a remarkable stroke of audacity, Charles married Anne of Brittany in 1491 after she had already been married by proxy to the Habsburg Holy Roman Emperor Maximilian I in a ceremony of questionable validity. Preoccupied by the problematic succession in the Kingdom of Hungary, Maximilian failed to press his claim. Upon his marriage, Charles became administrator of Brittany and established a personal union that enabled France to avoid total encirclement by Habsburg territories.

Francis II (Breton: Frañsez II, French: François II) (23 June 1433 – 9 September 1488) was Duke of Brittany from 1458 to his death. He was the grandson of John IV, Duke of Brittany. A recurring theme in Francis' life would be his quest to maintain the quasi-independence of Brittany from France. As such, his reign was characterized by conflicts with King Louis XI of France and with his daughter, Anne of France, who served as regent during the minority of her brother, King Charles VIII. The armed and unarmed conflicts from 1465 to 1477 and 1484–1488 have been called the "War of the Public Weal" and the Mad War (la Guerre Folle), respectively.

The War of the Public Weal (French: La guerre du Bien public) was a conflict between the king of France and an alliance of feudal nobles, organized in 1465 in defiance of the centralized authority of King Louis XI of France. It was masterminded by Charles the Bold, Count of Charolais, son of the Duke of Burgundy, with the king's brother Charles, Duke of Berry, as a figurehead. The rebels succeeded in attaining concessions from the crown after several months of fighting, though conflict would break out again between the league and the crown in the Mad War of 1485 in a decisive victory for the crown.