Summoned by Pope Pius IX, Vatican I (A.D. 1869-70) condemned, as erroneous, philosophical naturalism, pantheism, materialism, and atheism. It also affirmed each successor to the chair of the St. Peter obtains the primacy of Peter: as Vicar of Christ and sovereign head of the Church militant. Image above links to Tanner translation of the decrees. ISBN recommendation: 0-87840-490-2
Apostolic Constitution, promulgated December 8, 1854, establishing the dogma of the Immaculate Conception of Mary. “We declare, pronounce, and define that the doctrine which holds that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin, is a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful.” Image links to English translation.