locals were also Christian. The Arima were moved out in 1614 and replaced by the Matsukura. The new lord, Matsukura Shigemasa, hoped to advance in the shogunate hierarchy, and so he was involved with various construction projects, including the building and expansion of Edo Castle, as well as a planned invasion of Luzon in the Spanish East Indies (today a part of the Philippines). He also built a new castle at Shimabara. As a result, he placed a greatly disproportionate tax burden on the people of his new domain and further angered them by strictly persecuting Christianity. The policies were continued by Shigemasa's heir, Katsuie. The inhabitants of the Amakusa Islands, which had been part of the fief of Konishi Yukinaga, suffered the same sort of persecution at the hands the Terasawa family, which, like the Matsukura, had been moved there. Other masterless samurai in the region included former retainers of and Sassa Narimasa, both of whom had once ruled parts of Higo Province. Rebellion Start The discontented rōnin of the region, as well as the peasants, began to meet in secret on Yushima (also called "meeting island") and plot an uprising, which broke out on 17 December 1637, when the local daikan (magistrate) Hayashi Hyōzaemon was assassinated. At the same time, others rebelled in the Amakusa Islands. The rebels quickly increased their ranks by forcing all in the areas they took to join in the uprising. A charismatic 16-year-old youth, Amakusa Shirō, soon emerged as the rebellion's leader. The rebels laid siege to the Terasawa clan's Tomioka and Hondo castles, but just before the castles were about to fall, armies from the neighboring domains in Kyūshū arrived, forcing them to retreat. The rebels then crossed the Ariake Sea and briefly besieged Matsukura Katsuie's Shimabara Castle, but were again repelled. At this point they gathered on the site of Hara Castle, which had been the original castle of the Arima clan before their move to the Nobeoka Domain, but had since been dismantled. They built up palisades using the wood from the boats they had crossed the water with, and were greatly aided in their preparations by the weapons, ammunition, and provisions they had plundered from the Matsukura clan's storehouses. Siege at Hara Castle The allied armies of the local domains, under the command of the Tokugawa shogunate (during shogun Tokugawa Iemitsu's reign) with Itakura Shigemasa as commander-in-chief, then began