Vatican Council I was the 20th ecumenical (general) council of the Roman Catholic Church. Pope Pius IX summoned the council. It met in Rome from December 1869 to September 1870. It was the first ecumenical council since the Council of Trent had ended in 1563. About 800 bishops and other churchmen participated in the council. It brought together, for the first time, bishops from throughout the world. See Pius IX .
Vatican I took a stand against many of the secular (nonreligious) trends of the age. It promoted a centralized church extending beyond national boundaries, with supreme authority residing in the pope. The council proclaimed the infallibility of the pope’s teaching authority in the constitution named Pastor Aeternus (The Eternal Shepherd). The constitution states that the pope cannot commit error when he speaks as head of the church to define solemnly, in matters of faith and morals, what is to be accepted by all Roman Catholics as revelation from Jesus Christ and his apostles.
The council ended after the new Kingdom of Italy annexed Rome, causing the pope to withdraw to the Vatican Palace. Thus, the period of Vatican I witnessed both the peak of the pope’s religious authority and the loss of his civil power.
