After the Protestant Reformation of 1517, initiated by Martin Luther, there was a need to convene a General Council of the Catholic Church in order to bring about internal reform and preserve the religious unity of the faithful. After the establishment of the Holy Office of the General Roman Inquisition, which unified the inquisitorial activity exercised up to that time by the bishops in their dioceses, a General Council was solemnly convened on 13 December 1545 in the city of Trento, whose work, after a break of about a decade, was concluded in 1563. With the end of the Council, the era of the Catholic Reformation began. Although it was not possible to reconcile the schism and reunify the Church, the Catholic Restoration of the last decades of the 16th century took place in two ways: one defending the faith and the Church itself and one repressing the Counter-Reformation.