This council was summoned by Pope Pius IX by the bull Aeterni Patris of 29 June 1868. The first session was held in St Peter's basilica on 8 December 1869 in the presence and under the presidency of the pope.

The purpose of the council was, besides the condemnation of contemporary errors, to define the catholic doctrine concerning the church of Christ. In fact, in the three following sessions, there was discussion and approval of only two constitutions: "Dogmatic Constitution On The Catholic Faith" and "First Dogmatic Constitution on the church of Christ", the latter dealing with the primacy and infallibility of the bishop of Rome. The discussion and approval of the latter constitution gave rise, particularly in Germany, to bitter and most serious controversies which led to the withdrawal from the church of those known as "Old Catholics".

The outbreak of the Franco-Prussian war led to the interruption of the council. It was in fact never resumed, nor was it ever officially closed. As in other councils at which the pope was present and presided, the decrees were in the form of bulls, at the end of which was the clear declaration: "with the approval of the sacred council". Very large numbers attended this council, including, for the first time, bishops from outside Europe and its neighbouring lands. Bishops from the eastern Orthodox churches were also invited, but did not come.

The decrees of the council were published in various simultaneous editions. Later they were included in volume 7 of Collectio Lacensis ( 1892) and in volumes 49-53 of Mansi's collection (1923-1927). The collection use here is that entitled Acta et decreta sacrosancti oecumenici concilii Vaticani in quatuor prionbus sessionibus, Rome 1872. Comparison with other editions reveals no discrepancies, indeed absolute agreement.