The Shimabara Rebellion broke out on 17 December 1637 as peasants mainly Christian rose in revolt against their brutal daimyo or lord Matsukura Shigeharu. Although not only due to religious persecution the revolt was strengthened by the treatment of Christians in the Shimabara Peninsula. Here an estimated 23,000 out of a total population of 45,000 joined the revolt and the nearby Amakusa islands also joined the uprising. The initial popularity of the revolt was due in part to the charismatic leadership of Amakusa Shiro. Despite this the revolt failed to capture the castles of Shimabara and Tomioka without which the revolt was doomed to failure. The rebels then fortified themselves in the old castle of Hara on the Shimabara peninsular. Despite its poor state of repair and old fashioned design the castle held out for time, and several enemy commanders had reputations damaged by the siege of Hara. eventually the castle fell and the starving defenders were slaughtered. The end of the rebellion marked the end of the last serious opposition to the Tokugawa regime.