First Vatican Council

Opened on 8 December 1869. The constitution Dei Filius (24 April 1870) dealt with faith and reason, revelation and the possibility of knowing God by natural reason. The constitution Pastor aeternus (18 July 1870) defined the pope's primacy of jurisdiction and his infallibility when he defines ex cathedra a doctrine of faith or morals. It was suspended on 20 October 1870 after Italian troops occupied Rome.

Convoked by

Pope Pius IX

Catholic Church only (twentieth ecumenical council).