How did Henry VI’s periods of mental illness affect English politics?

King Henry VI’s periods of mental illness were a critical catalyst for the Wars of the Roses, as his incapacity for government created a power vacuum that intensified factional rivalries.12

During his first major breakdown (July 1453–December 1454), the government was left without effective leadership. This allowed Richard, 3rd duke of York—who held a strong hereditary claim to the throne—to be appointed protector of the realm by Parliament in March 1454. This appointment was fiercely opposed by Margaret of Anjou, who sought to protect the succession rights of her infant son, Edward.345

When Henry recovered in December 1454, he was persuaded by Margaret to dismiss York and restore the rival Beaufort faction to power. This reversal forced York to take up arms for self-protection, leading directly to the first battle of the wars at St. Albans in 1455. Ultimately, Henry’s inability to maintain stable rule and his susceptibility to the influence of competing political parties transformed the court into a battleground, fueling the long-term conflict between the houses of Lancaster and York.341