The First Vatican Council was convoked by Pope Pius IX on 29 June 1868, after a period of planning and preparation that began on 6 December 1864. This twentieth ecumenical council of the Roman Catholic Church, held three centuries after the Council of Trent, opened on 8 December 1869 and adjourned on 20 October 1870. Unlike the five earlier General Councils held in Rome, which met in the Lateran Basilica and are known as the Lateran Councils, it met in the Vatican Basilica, whence its name of First Vatican Council. Its best-known decision is its definition of papal infallibility.
According to Raffaele De Cesare:
However, following the Austro-Prussian War, Austria had recognized the Kingdom of Italy. Consequently, because of this and other substantial political changes: "The Civiltà Cattolica suggested that the Papal Infallibility should be substituted for the dogma of temporal power ..." 
The Council was convoked to deal with the contemporary problems of the rising influence of rationalism, liberalism, and materialism. Its purpose was, besides this, to define the Catholic doctrine concerning the Church of Christ. There was discussion and approval of only two constitutions: the Dogmatic Constitution on the Catholic Faith and the First Dogmatic Constitution on the Church of Christ, the latter dealing with the primacy and infallibility of the bishop of Rome. The first matter brought up for debate was the dogmatic draft of Catholic doctrine against the manifold errors due to Rationalism.
The doctrine of papal infallibility was not new and had been used by Pope Pius in defining as dogma, in 1854, the Immaculate Conception of Mary, the mother of Jesus. However, the proposal to define papal infallibility itself as dogma met with resistance, not because of doubts about the substance of the proposed definition, but because some considered it inopportune to take that step at that time. A minority, some 20 percent of the bishops, feared that defining papal infallibility would alienate some Catholics, create new difficulties for union with non-Catholics and would provoke interference by governments in Church affairs. Those who held this view included most of the German and Austro-Hungarian bishops, nearly half of the Americans, and one third of the French; of the Eastern Catholics, most of the Chaldaeans and Melkites, and a few Armenians shared this view. Only a few bishops appear to have had doubts about the dogma itself.
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