Henry III became King of England within days of his ninth birthday, inheriting a country embroiled in a bitter, entrenched war with itself. As he grew into adulthood, Henry had to manage the transition to a personal rule, wrenching power from men who had held it almost unchecked for years. Failures abroad led to trouble back in England as restless barons became disillusioned. They found a figurehead in Simon de Montfort, a man who would transform himself to a de facto king. Imprisoned and stripped of his power, Henry would again have to fight for his kingdom, relying on his immensely capable son. Henry's reign would spell over half a century of highs and lows in a country crying out for stability; the final measure of Henry’s achievement displayed in the crown that he left to his son, Edward I.