Battle of Castillon
Then, in August 1453, Henry VI suffered a catastrophic mental breakdown, perhaps brought on by the news of the defeat at the Battle of Castillon in Gascony, which finally drove English forces from France. He became completely unresponsive, unable to speak, and had to be led from room to room. The Council tried to carry on as though the king's disability would be brief, but they had to admit eventually that something had to be done. In October, invitations for a Great Council were issued, and although Somerset tried to have him excluded, York (the premier duke of the realm) was included. Somerset's fears were to prove well grounded, for in November he was committed to the Tower.