The Counter-Reformation is the name given to the self-imposed disciplining of the Catholic Church which started in the 16th century to 'counter' the successes of the Protestant Reformation.
It was to a great extent based on the dictates of the Council of Trent - a series of meetings of the ruling body of the church - which included increasing the power of the Pope, and specifying the type of imagery it felt would best serve the needs of the Church. The active aspects of the movement included the Inquisition, a court which clamped down on heresy, and the establishment of new dynamic religious orders, such as the Jesuits.
In Europe the Counter-Reformation was most effective in Italy and Spain.