The agreement that made Richard of York heir to Henry VI in 1460 was the Act of Accord.
Passed by the English Parliament on 25 October 1460, the act created a temporary settlement during the Wars of the Roses. Richard, Duke of York, had a strong hereditary claim to the crown and had challenged the authority of the Lancastrian King Henry VI.
The compromise allowed Henry VI to remain king for the rest of his life, but it disinherited his son, Edward of Westminster, Prince of Wales. On Henry’s death, the crown was to pass to Richard of York and then to Richard’s heirs. The arrangement therefore made York heir apparent without immediately deposing Henry.
The settlement did not end the conflict. Queen Margaret of Anjou and Lancastrian supporters rejected the disinheritance of her son. Richard of York was killed at the Battle of Wakefield in December 1460, only weeks after the act was passed, and his son Edward later claimed the throne as Edward IV. The Act of Accord thus became a pivotal legal milestone in the Yorkist path to power.