Treaty of Amiens (1423)

The Treaty of Amiens was a 1423 defensive agreement between John of Lancaster, 1st Duke of Bedford, Philip II, Duke of Burgundy and Arthur, Earl of Richmond (on behalf of John V, Duke of Brittany), in which the three parties acknowledged Henry VI of England as King of France, and agreed to aid each other against the Valois claimant, Charles VII of France.

The Treaty of Amiens was signed on 13 April 1423, and formed in the aftermath of the Treaty of Troyes. It helped maintain the Anglo-Burgundian alliance until 1435, and the basis of the dual-monarchy of the two kingdoms of England and France first formed by King Henry V of England at Troyes.

The Treaty of Amiens arranged the marriage of the John, Duke of Bedford to the Duke of Burgundy's younger sister, Anne of Burgundy, and the marriage of Arthur, Earl of Richmond, to the Duke of Burgundy's older sister Margaret of Burgundy, widow of Louis, Dauphin of France. Furthermore, the treaty stated that all three of the parties would willingly acknowledge Henry VI of England as King of France, as had been promised by their oaths taken at the Treaty of Troyes two years before.

As formalised by the Treaty of Troyes, Henry V and his heirs would inherit the Kingdom of France after Charles VI's death. However Henry V died four weeks before the death of Charles VI, and so never inherited the French throne.

...
Wikipedia