England
Cade's Rebellion
Little wonder, then, that a rebellion broke out in 1450. It began in the southern counties, in Sussex and Kent. It was more than just a peasant revolt, for many participants were lesser knights or small merchants. It was led by one Jack Cade, who gathered thousands into something more than a mob but something less than an army.
As every English rebel had done, he marched on London. His followers occupied the great guildhall of the city and opened the prisons. Looting broke out here and there, but the chief victim was Lord Saye, the royal treasurer, who was dragged out and executed by a mob. Within a matter of days the citizens of London had driven most of Cade's followers out of the city, though Jack himself was holed up in the Tower.
Cade was given a pardon by the king (Henry was not at this time insane, but neither was he in control of much). Trusting to this, he left the city peacefully, whereupon he was hunted down and killed.
The whole business is not really part of the Wars of the Roses, but it's worth relating to show how out of joint were the times. Defeat in war, economic troubles, incompetent leaders and a king worse than incompetent. England needed someone to step forward. The trouble was, more than one stepped forward, and each of them had his own army.