Why was John Dudley beheaded?

John Dudley, the Duke of Northumberland, was beheaded in 1553 primarily due to his role in the attempted usurpation of the English throne. After the death of King Edward VI, Dudley supported the claim of Lady Jane Grey, Edward's cousin, in an effort to maintain Protestant control. However, when Mary I, a Catholic and Edward's half-sister, successfully claimed the throne, Dudley was arrested, tried for treason, and ultimately executed for his part in the failed coup. His ambitions and political maneuvers ultimately led to his downfall.