The Reformation began in the 1500s led by reformers such as Martin Luther, John Calvin, and King Henry VIII who challenged the authority and teachings of the Catholic Church. Luther posted his 95 Theses criticizing the Church in 1517 which sparked the Protestant Reformation. The printing press helped spread Protestant ideas. The Counter Reformation was launched by the Catholic Church including through the Jesuits and the Council of Trent to combat heresy and reform the Church. This led to a divided Europe and era of religious wars between Protestant and Catholic states.