The Reformation began in the 15th-16th centuries as reformers like John Wycliffe, John Huss, and Martin Luther spoke out against corruption and doctrines of the Roman Catholic Church. They emphasized scripture alone, faith alone, and the priesthood of all believers. Their teachings spread Protestantism and influenced others like Ulrich Zwingli and John Calvin. In response, the Roman Catholic Church launched the Counter Reformation to defend its doctrines through means like the Jesuits and Inquisition. Religious wars broke out across Europe during this period of upheaval and change in the Christian church.