Vatican Council, First, or Vatican I (1869–70). A Roman Catholic council. Called by Pope Pius IX. This council adopted only two constitutions, despite the advance preparation of fifty-one schemata. The constitution on faith, Dei Filius, dealt with God as creator, revelation, faith, and faith's relationship to reason, adopting positions similar to those of St Thomas Aquinas. The schema on the Church was not voted on; instead, the question of the papacy was brought forward, although many (e.g. J. H. Newman) regarded this as inopportune. The constitution Pastor Aeternus defined the primacy of the pope and also his infallibility when he speaks ex cathedra, i.e. when as chief pastor of the Church he defines a doctrine on faith or morals to be held by the whole Church.

After Italian troops occupied Rome, the Council was suspended in Oct. 1870. It never reconvened, and the incompleteness of its work led to a serious imbalance in RC Church teaching.

Vatican Council, First (1869–70) Twentieth ecumenical council of the Roman Catholic Church. Convened by Pope Pius IX to refute various contemporary ideas associated with the rise of liberalism and materialism, it is chiefly remembered for its declaration of papal infallibility.