Pius IX was elected to the papacy in 1846, a very unstable time in Italian history. Although Pius was the first of the modern popes, who held little modern ideas, he managed to retain a place in the hearts of most Catholics at the time. Pius IX continually stressed the teachings and moral lessons of Catholicism. In 1854, Pius wrote The Immaculate Conception of Mary, a Christian document that absolved the Virgin Mary from the fall of Adam and original sin. This document served to increase the gap between Roman Catholics and both Protestants and Eastern Orthodox. This document is considered to be very reliable in it self and its source being that it was written and instituted by the Papacy of Pius IX.
The document itself is fairly brief, but on the same token is very precise within the message of the words. Pius starts by stating, in few words, the simple moral truth that we are all human, and therefore all born of original sin; and because of this, we honor "God the Father through his son" and through this honor we free the Virgin Mary from original sin. Pius states the he uses the authority of Jesus Christ, the Apostles Peter and Paul, and that of humanity. .
The section of the document that I found most interesting is towards the end. Pius states that this document is to be "believed by all the faithful", and as a result, if someone should "think in their hearts otherwise", they shall be condemned. Pius goes on to state that any "external" expression of disbelief would be punishable under law. I think this section of the document has special significance for several reasons; first, it tends to reflect the mind-set of clergymen at the time. Being that there was a Revolution taking place in Italy, and especially in Rome, and still the struggles against and threats of Protestantism and Eastern Orthodoxy, this document, heavily rooted in Roman Catholicism was something that must be accepted by all Catholics.