The Counter-Reformation was a reaction by the Catholic Church against the Protestant Reformation. It began in the 16th century and aimed both to reform the Catholic Church and counter the spread of Protestantism. The Jesuits played a key role in the Counter-Reformation through education. Pope Paul III convened the Council of Trent in 1545, which enacted reforms to address issues like corruption and clarify Catholic doctrine. The Inquisition was established in 1542 to combat heresy and control religious doctrine and practice. The Counter-Reformation achieved victories like restoring Catholic domination in Poland and Bohemia.