Long rebellion by the Hussite Bohemians against the authority of the Holy Roman Empire, at least as represented by the German ruling class, and the Church. The rebellion was triggered by the mistreatment of John Huss, principal of the University of Prague, and a theologian who opposed the worldliness of the church. He attended the council of Constance (1415) having been given a safe conduct by the Emperor Sigismund. However, the council condemned him as an heretic, persuaded Sigismund to betray him, and burnt him at the stake. This outrage fanned the flames of revolt in Bohemia. Ordinarily, the Bohemians would have had no chance against the Imperial forces, and they were nearly always outnumbers. The odds were altered by the Bohemia tactics - the use of the 'wagenburg', whereby the army marched with heavily fortified wagons. When battle was close, the wagons were formed up into a square, the gaps fortified, and the Germans found themselves attacking a fortification. The Bohemians were also the first to use large numbers of hand guns. The clumsy hand guns of the time were much better suited to use from within the wagons than on the open battlefield. Once the enemy attacks had been repulsed, the troops within the 'wagonburg' opened sally points and counter-attacked the by now demoralised enemy. Five Imperial invasions of Bohemia failed, and the Bohemians were even able to mount offensive actions over their borders. The rebellion finally ended after the battle of Lipan (26 June 1434), where the moderate element amongst the Bohemians, having gained good terms from the Emperor, defeated the extremist 'Taborite' party, ending the rebellion.