The First Vatican Council was summoned by Pope Pius IX by the bull Pastor Aeternus of June 29, 1868. The first session was held in Saint Peter's Basilica on December 8, 1869. It was the 20th ecumenical council of the Catholic Church. Nearly 800 church leaders attended. They met ninety-three times between December 8, 1869 and September 1, 1870.
The Pope's two primary purposes were to define the dogma of Papal Infallibility and to obtain confirmation of the position he had taken in his Syllabus of Errors (1864), condemning a wide range of positions associated with rationalism, liberalism, and materialism.
In the three sessions, there was discussion and approval of only two constitutions: Dei Filius, the Dogmatic Constitution On The Catholic Faith (which defined, among other things, the sense in which Catholics believe the Bible is inspired by God) and Pastor Aeternus, the First Dogmatic Constitution on the Church of Christ, dealing with papal primacy and infallibility.
The definition of papal infallibility was controversial, not because many did not believe the pope to be infallible when defining dogma, but because many who did so believe did not think it prudent to define the doctrine formally. John Henry Newman, for instance, thought such a formal definition might push away potential converts. Some feared it might lead to renewed suspicion of Catholics as having a foreign allegiance. This view was taken by two-thirds of the bishops from the United States and many from France and Germany.
About 60 members of the council effectively abstained by leaving Rome the day before the vote. Archbishop Antonio María Claret y Clará, confessor to the Spanish royal court and founder of the Claretians (Claretian Missionaries), strongly condemned the "blasphemies and heresies uttered on the floor of this Council," and was one of the strong defenders on the issue of papal infallibility and the primacy of the See of Rome. He was the only member of the council to be canonized as saint (beatified in 1934 and canonized by Pope Pius XII in 1950). He died in a Cistercian monastery in Fontfroide, France, in October 24, 1870. The discussion and approval of the constitution gave rise to serious controversies which led to the withdrawal from the church of the Old Catholics.
The outbreak of the Franco-Prussian War interrupted the council. It was suspended following the entry of the Italian Army in Rome, the so-called capture of Rome, and never resumed. It was not officially closed until decades later in 1960 by Pope John XXIII, when it was formally brought to an end as part of the preparations for the Second Vatican Council. The First Vatican Council marked the triumph of the ultramontanist movement, which supported a central Vatican-based government of the Church. An increasing awareness of their own identity among Roman Catholics worldwide was detected, and the numbers of converts to Catholicism as well as the numbers of vocations to the religious and priestly life increased, along with clearly pro-Catholic political activity of Catholics in their native countries. Along with this, a stronger involvement of laymen in the outward working of the Catholic Church evolved, and the council would indirectly lead to the stimulation of the Liturgical Movement, which would particularly flourish under Pope Pius X.