Ziska's first policy was to arm the Bohemians. He introduced among them the "thunder-guns"--small field-pieces, which had been first used at the battle of Agincourt, between England and France, three years before; he shod the farmers' flails with iron, and taught them to crack helmets and armor with iron maces; and he invented a system of constructing temporary fortresses by binding strong wagons together with iron chains. Sigismund does not seem to have been aware of the formidable character of the movement until the end of his war with the Turks, some months afterwards, and he then persuaded the Pope to summon all Christendom to a crusade against Bohemia. During the year 1420 a force of 100,000 soldiers was collected, and Sigismund marched at their head to Prague. The Hussites met him with the demand for the acceptance of the following articles: 1.--The word of God to be freely preached; 2.--The sacrament to be administered in both forms; 3.--The clergy to possess no property or temporal authority; 4.--All sins to be punished by the proper authorities. Sigismund was ready to accept these articles as the price of their submission, but the Papal Legate forbade the agreement, and war followed. On the 1st of November, 1420, the "Crusaders" were totally defeated by Ziska, and all Bohemia was soon relieved of their presence. The dispute between the moderates and the radicals broke out again; the idea of a community of property began to prevail among the Taborites, and most of the Bohemian nobles refused to act with them. Ziska left Prague with his troops and for a time devoted himself to the task of suppressing all opposition through the country with fire and sword. He burned no less than 550 convents and monasteries, slaying the priests and monks who refused to accept the new doctrines; but he proceeded with equal severity against a new sect called the Adamites, who were endeavoring to restore Paradise by living without clothes. While besieging the town of Raby, an arrow destroyed his remaining eye, yet he continued to plan battles and sieges as before. The very name of the blind warrior became a terror throughout Germany.