The Counter-Reformation was a movement within the Roman Catholic Church that began in the 16th century as a response to the Protestant Reformation. It aimed to reform the Church from within and to counter the spread of Protestantism. Key elements included the establishment of new religious orders, such as the Jesuits, and the reaffirmation of Catholic doctrines at the Council of Trent. This movement also involved efforts to improve the education of clergy and to address issues of corruption and abuse within the Church. The Counter-Reformation played a significant role in revitalizing the Catholic Church and solidifying its influence in Europe during the late Renaissance.